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COLLIER    COBB 

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UNIVERSITY  OF  N.C.  AT  CHAPEL  HILL 


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THE  LIBRARY  OF  THE 
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AN   OUTLINE 


OF 


GENERAL   GEOLOGY, 


WITH   COPIOUS  REFERENCES. 


DESIGNED  FOR  THE  USE  OF  BOTH  GENERAL  AND  SPECIAL 
STUDENTS. 


BY 

THEO.  B.  COMSTOCK,  B.Ag.,  B.S., 

In  Charge  of  Department  of  Geology,  Paleontology  and  Economic  Geology 
in  The  Cornell  University. 


The  laws  of  Nature  are  fixed  and  invariable. 
Any  given  cause  always  produces  the  same  effect 


ITHACA,  N.  Y. 

PRINTED  FOR  THE  AUTHOR  AT 

THE    UNIVERSITY    PRESS, 
1878 


5^ 

<< 


PREFACE. 

This  little  volume  is  an  amplification  of  a  "Syllabus"  of  the 
author's  elementary  lectures  to  a  mixed  class  of  students  in  the 
Cornell  University.  In  this  institution,  the  subjects  of  Eco- 
nomic Geology  and  Palaeontology  are  treated  in  more  special 
courses  to  which  no  student  is  eligible  who  has  not  passed  the 
examination  in  this  general  course.  The  class  being  made 
up  of  members  with  quite  various  acquirements  and  purposes, 
it  has  been  a  matter  of  no  slight  difficulty  to  arrange  a  Vade- 
mecum  intended  both  to  meet  the  wants  of  those  who  aim  at 
the  highest  proficiency  in  General  Geology  and  at  the  same 
time  to  be  sufficiently  concise  and  simple  for  such  as  desire  but 
a  cursory  review  of  the  subject  as  a  means  of  general  culture. 

It  is  evident  that  this  Outline  will  serve  its  best  purpose 
when  used  in  connection  with  a  course  of  lectures.  The 
author,  in  preparing  it,  has  not  been  unmindful  of  the  fre- 
quent requests  of  teachers  and  others  for  a  similar  work,  which 
shall  embody  the  best  deductions  and  latest  discoveries,  with 
references  to  authorities,  without  obliging  the  general  student 
to  waste  his  time  in  unsuccessful  efforts  to  collate  the  facts  and 
principles  of  the  science,  scattered  through  hundreds  of  works, 
many  of  which  are  inaccessible. 

The  subject  matter  of  the  synopsis  is  arranged  throughout 
systematically  in  such  a  manner  as  to  provide  the  student  with 
means  of  ready  reference  in  the  lecture-room  and  in  the  study, 
but  it  cannot  in  any  degree  supply  the  place  of  collateral  read- 
ing, much  as  it  may  aid  the  memory  in  classifying  what  has 
been  read.  Some  subjects  are  much  more  minutely  outlined 
than  others,  and,  as  a  rule,  it  may  be  regarded  as  desirable  to 
devote  most  attention  in  outside  reading  to  those  subjects 
which  are  here  least  clearly  explained.  Many  will  find  it  un- 
necessary to  take  full  notes  of  the  lectures,  though  nothing 
should  be  left  unrecorded  which  may  require  further  study,  or 


4  PREFACE. 

which  is  of  the  nature  of  statistics  or  technicalities.  In  gen- 
eral, the  blank  pages  should  be  used  for  recording  definition* 
of  technical  terms,  as  they  are  explained,  and  for  the  copying 
of  such  diagrams  and  other  illustrations  as  may  be  placed  up- 
on the  blackboard  during  the  course. 

No  text-book  will  be  necessary;  several  are  recommended 
as  valuable  for  general  use,  and  those  who  can  afford  it  will  do 
well  to  purchase  either  Dana's  "Manual  of  Geology"  (Re- 
vised Edition,  1874),  or  Le  Conte's  "Elements  of  Geology," 
the  latter  being  of  special  value  in  certain  particulars.  Other 
general  works,  such  as  the  best  treatises  on  Physical  Geogra- 
phy, Jukes  and  Geikie's  "  Manual  of  Geology,"  Lyell's  "  Stu- 
dents' Elements  of  Geology,"  etc.,  may  be  briefly  reviewed  be- 
fore the  class  at  the  beginning  of  the  course. 

Works  of  reference  for  special  topics,  and,  in  many  cases, 
titles  of  papers  in  periodicals,  even  when  not  readily  accessible 
are  given  together  in  a  list  at  the  end  of  this  volume,  each  with 
an  index  number  by  which  it  is  referred  to  at  points  in  the 
body  of  the  Outline  [R.  1,  2,  3,  etc.]  The  occurrence  of  fig- 
ures in  black,  type  in  the  text  indicates  that  the  works  sug- 
gested are  specially  devoted  to  the  subject  under  discussion  in 
that  portion  of  the  Outline.  Some  further  hint  as  to  the  char- 
acter of  works  is  given  in  the  List  of  References  by  printing 
in  Italics  the  titles  of  such  works  as  are  particularly  adapted  to 
the  needs  of  general  students.  At  the  same  time  the  exercise  of 
some  judgment  will  be  required  to  prevent  the  overlooking  of 
works,  which,  though  special  in  character,  may  contain  matter 
of  importance  to  the  most  general  students.  To  avoid  this  diffi- 
culty references  to  particular  pages  have  been  introduced  in 
almost  every  case  of  the  kind. 

The  author  is  conscious  of  many  imperfections  (the  result 
of  pressing  demands),  which  have  made  him  hesitate  to  seek 
for  a  wider  field  than  is  presented  in  his  own  lecture-room,  but 
he  will  be  well  pleased  if  his  offering  shall  be  found  in  some 
slight  degree  serviceable  to  even  a  very  few  other  teachers  and 
students.  If  the  judgment  be  at  all  favorable,  suggestions 
concerning  improvements  in  a  later  edition  are  respectfully 
solicited. 

THEO.  B.  COMSTOCK. 
Ithaca,  N.  Y.,  Nov.  15,  1878. 


COURSE  I.-GENERAL  GEOLOGY. 


Abbreviations  are  used  as  follows :  H.  for  hardness  :  Gr.  for  specific  gravity ;  Comp. 
for  composition  ;  Sol.  for  soluble ;  Insol.  for  insoluble ;  Infus.  for  infusible ;  Var.  for 
variety  (or  varieties) ;  Cryst.  for  crystallization;  CI.  for  cleavage;  Temp,  for  tempera- 
ture ;  Ref.  for  general  references ;  R.  for  special  references. 


PART  I.-INTRODUCTION. 

i.  Nature  and  Science;  abuse  of  the  terms. 

2.  Natural  Science;  its  divisions:  A.  Cosmical;  As- 
tronomy. B.  Telluric.  I.  Physical;  Physics,  Chemistry. 
II.  Geognostic ;  Mineralogy,  Geognosy.  III.  Biological ;  Bot- 
any, Zoology.  IV.  Geographical j  Geography  (Mathematical, 
Physical).  V.  Historical /  History,  Archaeology.  VI.  Psy- 
chical;  Psychology,  Meta- Physiology. 

3.  Position  and  Relations  of  Geology  in  this  system; 
central,  dependent  on  first  three  divisions,  contributing  to  last 
three. 

4.  Cultivating  Power  of  Geology. 

5.  Scope  of  the  science. 

6.  Divisions  :  A.  Physiography.  B.  Geognosy.  C.  Dy- 
namical Geology.    D.  Palaeontology.    E.  Stratigraphy. 

F.  Historical  Geology,  including  Archaeology,  in  part. 

G.  Economic  Geology. 

7.  Methods  of  Study  and  modes  of  reasoning. 

8.  Theories  ;  their  uses  and  abuses,  as  illustrated  by  his- 
tory. 

g.  Outline  of  present  course;  to  include  Physiography, 
Geognosy,  Dynamical  Geology,  and  Historical  Geology ;  sep- 
arate courses  in  Economic  Geology  and  Palaeontology. 

5 


6  GENERAL  GEOLOGY. 

PART  II.-PHYSIOGRAPHY. 

DIVISION  A.-COSMICAE  CONSIDERATIONS. 

1.  Physiography  treats  of  earth's  surface  features,  "forms 
of  relief,"  movements  of  air  and  water,  distribution  of  life 
forms,  etc. ;  in  brief,  review  of  exterior  features  and  phenomena 
of  the  globe. 

2.  Cosmical  Relations  of  earth,  a.  Position  in  space. 
b.  Motions,  (i)  through  space;  (2)  annual  revolution;  (3) 
diurnal  revolution,  c.  Solstices  and  equinoxes,  d.  Eccentricity 
of  orbit ;  variations  between  circle  and  ellipse,  e.  Obliquity  of 
axis  not  constant,  but  changes  slight  and  gradual,  f.  Preces- 
sion of  equinoxes. 

3.  General  Conclusions  based  upon  cosmical  variations 
in  the  past,  as  affecting  climate  and  distribution  of  life. 

4.  Origin  of  Earth  according  to  Nebular  Hypothesis. 

Ref. : — General  works  on  Astronomy;  also,  R. 
4,  6,  8,  11,  etc. 

DIVISION  B.-CONCERNING  THE  EAND. 

1.  Shape  of  Earth. 

2.  Distribution  of  Land  and  "Water :  a.  275  parts  of 
water  to  100  parts  of  land,  or  nearly  as  8  to  3.  b.  N.  Hemi- 
sphere about  f  land  ;  W.  Hem.  about  \  land;  N.  Temp.  Zone 
\  land,  \  water,  c.  Divide  globe  into  hemispheres,  taking  An- 
tipodes Is.  and  point  near  London  as  poles,  and  one  hem.  will 
contain  TV  of  all  the  land.  d.  Only  gV  of  land  has  land  an- 
tipodes. 

3.  Coast  Line  : — Europe  has  -^h-  of  its  area;  Asia,  ■&$', 
Africa,  ^ ;  N.  A.,  -g-b;  S.  A.,  ^;    Australia,  ^. 

4.  Homomorphism.  a.  Occident  and  Orient;  orient  = 
2  Occidents ;  Polynesia  represents  modern  submergence  of 
tract  connecting  Australia  with  mainland,  b.  Occidents  form- 
ed by  two  triangles  pointing  southward,  united  by  isthmus  with 
archipelago  on  one  side,  peninsula  on  other,  c.  Island  (or 
group)  near  extremity  of  peninsula,  often  to  S.  E.  d.  Gulf  on 
W.  side  of  S.  triangle,  e.  N.  shores  low,  not  deeply  indented, 
S.  shores  deep-cut,  commonly  with  bold  peninsulas ;  promon- 
tories more  frequently  pointing  southward,  f.  Extreme  N.  and 
extreme  S.  points  of  each  continent  nearly  on  same  meridian. 

5.  Forms  and  Character  of  Land  Surface,     a.  Dis- 


PHYSIOGRAPHY.  7 

tribution  and  general  character  of  (1)  Lowlands,  (2)  Plateaus, 
and  (3)  Mountains.  b.  Use  of  terms  Serra  (Portuguese), 
Sierra  (Span.),  Peak,  Mountain,  Range,  Cham,  Cordillera,  etc. 
C.  Distinctions  between  Hill,  Mountain,  Butte,  Bench  and 
Mesa.  d.  Relations  of  plateaus  to  mountain  systems,  e.  Ex- 
amples : 

(1)  Lowlands  :  Mississippi  Valley,  Lower  Conn.  Valley ;  (usually  under 
1000  ft.)  (2)  Plateaus:  Gt.  Basin,  Utah,  5000  ft.;  Colorado  Desert, 
Wyo.,  7000  ft.  ;  N.  Y.  State  largely  a  plateau,  1500  ft.  to  2500  ft.  ;  Quitos 
Plateau,  10,000  ft.  ;  Bolivia,  13,000  ft.  ;  Thibet  (bet.  Himalayas  and  Kuen 
Lun  Mts.),  11,500  ft.  to  13,000  ft.  ;  Desert  of  Gobi,  Mongolia,  4000  ft.  ; 
Sahara,  1500  ft.  (3)  Mountains  various  heights:  Appalachians,  2000  ft. 
to  6500  ft.  :  Rocky  Mts.,  9000  ft.  to  14,500  ft.  ;  Andes,  13,000  ft.  to  25,000 
ft. ;   Himalayas,  even  29,000  ft. 

6.  Kinds  of  Mountains.  (1)  Narrow,  with  elevated 
ridges,  as  Andes  and  Himalayas;  (2)  Broad,  much  folded,  as 
Jura  and  Appalachians;  (3)  Broad,  with  high  plateaus,  as 
Rocky  Mts. 

7.  Mountain  Slopes  ;  often  very  gradual,  seldom  abrupt 
except  in  peaks. 

Examples :  Rocky  Mts.,  E.  slope  8  ft.  to  12  ft.  per  mile,  W.  slope  not 
much  greater;  Andes,  E.  60  ft.,  W.  100  ft.  to  150  ft.  per  mile;  Appala- 
chians, irregular. 

8.  Relief  Systems.  a.  Laws  of  Vertical  Config- 
uration. 

( 1 )  Each  continent  has  elevated  borders  and  an  interior  basin. 

(2)  Highest  land  near  middle  of  each  border,  lower  southward,  lowest 
northward. 

(3)  Higher  and  steeper  border  faces  larger  oceatt  [R.  13  (II,  vols,  iii,  398, 
iv,  92,  1847,  and  xxii,  335,  1S56)]. 

(4)  Interior  drainage  system  of  each  occide7it  in  a  measure  homologous, 
and  N.  and  S.  triangles,  each  to  each,  more  evidently  related. 

b.  Laws  of  Horizontal  Disposition. 

(1)  Every  mountain  chain  belongs  to  one  of  two  systems  of  trend — N.E. 
XS.W.  or N.IV.XS.E. 

(2)  Each  continent  has  " N.E.  system"  on  E.  border,  and  "JV.JV. 
system  "  on  IV.  border. 

(3)  Oceanic  islands  are  arranged  iti  linear  groups  following  one  or  other 
of  the  two  "  systems  of  trend" ;  (rule  follows  from  the  fact  that  the  islands 
are  merely  summits  of  submerged  mountain  chains). 

(4)  Outlines  of  continents  lie  in  direction  of  great  circles  of  the  sphere 
[R.  12,  13  (II,  xxv,  130)]. 

Ref. : — 1  (Part  I),  4-5,  10  (Part  I),  11,  12,  23. 

DIVISION  C— AS  REGARDS  THE  WATER. 

i.  Comparison  of  Oceans:  a.  Areas  and  probable 
depths:  Atlantic,  2800  miles  wide;  Pacific,  6000  miles  wide, 
area  to  620  S.,  62,000,000  miles,     b.  Sources  of  error  in  sound- 


8  GENERAL  GEOLOGY. 

ing :  (i)  Pressure  at  great  depths ;  (2)  Submarine  currents ;  (3) 
Projecting  ledges,  c.  Some  forms  of  sounding  apparatus ; 
bathometer,  d.  Estimation  of  depth  by  means  of  earthquake 
waves. 

Depth  quite  variable;  Atlantic  along  Telegraphic  Plateau  only  from 
6000  ft.  to  15,000  ft. ;  Gulf  of  Mexico,  about  6000  ft.  Earthquake-wave 
calculations  make  N.  and  S.  Pacific  from  12,000  ft.  to  13,000  ft.,  average. 
Capt.  Ross  sounded  28,000  ft.  without  bottom,  and  Capt.  Denham  46,000  — 
ft.,  striking  bottom,  both  in  Pacific.  Between  India  and  E.  Indies,  aver- 
age barely  300  ft. ;  also  same  depth  between  Australia  and  adjacent  islands 
north  ;  N.  Amer.  and  Asia  separated  by  similar  area  600  ft.  in  depth 
[R.  14,  15  (II,  ii.,  278)]. 

2.  Sea  Water ;  a.  Sp.  gr.  b.  Specific  heat ;  effect  on 
climate,  c.  Temperature ;  widely  different  on  opposite  sides 
of  same  ocean  (to  be  explained  beyond). 

3.  Ocean  Movements :  Waves,  Tides  and  Currents. 
I.  Waves;  caused  by  winds  and  by  earthquakes.  II.  Tides. 
a.  Cause  of  variation  in  height  at  different  points,  b.  Progress 
of  Tidal  Movement,  c.  Peculiarity  seen  on  Amazonas;  cur- 
rent in  same  direction  with  rise  and  fall  of  tide.  d.  Effect  of 
wind  upon  tides,  e.  Theory  of  lunar  action,  with  cause  of 
"neap"  and  "spring"  tides.      III.   Currents x  and  Indraughts. 

a.  Equatorial  Drift ;  westward,  caused  by  unequal  velocity  of 
earth  at  poles  and  equator,  partly,  also,  by  uneven  temperature. 

b.  Gulf  Stream;  80  to  100  miles  from  coast,  of  great  depth, 
follows  sinuosities  of  coast  line ;  surface  velocity  and  cross- 
section,  c.  Eastern  Drift  near  6o°,  N.  and  S.  Lat.  d.  Arctic 
Indraught,  e.  Labrador  Current,  f.  Rennel's  Current,  g. 
Similar  System  in  S.  Atlantic  and  in  other  oceans. 

4.  Sargasso  Sea. 

5.  Climate,  as  influenced  by  oceanic  currents. 

6.  Circulation  of  Water  from  sea  to  land  and  return. 
a.  Drainage  Systems,  b.  Peculiar  Water-sheds :  "Crown  of 
the  Continent,"  in  neighborhood  of  Yellowstone  National 
Park ;  S.  Pass,  Rocky  Mts. ;  "  Two-Ocean  Pass ; "  Orinoco  and 
Cassiquiari;  Madeira  and  La  Plata;  Mississippi  and  Red 
River  of  the  North. 

Ref.: — 1  (Part  I),  4-8,  10  (Part  I),  n  ;   Dana, 
J.  D.,  in  12  (II,  xxvi,  231)]. 

1  Ocean  currents  are  named  according  to  direction  towards  which  they  flow;  thus,  an 
eastern  current  flows  eastward,  a  western  current,  westward,  and  so  on. 


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PHYSIOGRAPHY.  9 

DIVISION  D.-RELATING  TO  THE  ATMO- 
SPHERE. 

1.  Composition  and  Character,  a.  Normally  con- 
tains: O,  21  parts;  N,  79  parts;  C02,  -^  to  TV;  H20,  vari- 
able, b.  Thickness,  as  determined  by  observations  of  meteors, 
by  polarization  of  light  (M.  Liais),  etc.  c.  Pressure;  amount, 
periodic  variations,  etc.  d.  Temperature ;  radiation,  effects 
upon  climate,  e.  Refraction;  twilight,  absence  at  equator. 
f.  Ozone  in  air. 

2.  Atmospheric  Movements.1  a.  N.E.  and  S.  E. 
Trade  winds  and  Counter-trades,  b.  Calms,  c.  High  Western 
Current,  d.  Summer  and  Winter  changes,  e.  Some  theories 
regarding  currents,  f.  Periodic  Currents,  g.  Local  Currents. 
h.  Storms. 

Ref. : — Works  on    Physics  and   Meteorology ; 
R.  1  (Part  I),  4-8,  10,  11,  18,  23. 


DIVISION  E.— CEIMATIC  CONDITIONS. 

1.  Climate;  general  considerations,  a.  Latitude  alone 
affects  temperature,  evaporation,  precipitation.  b.  Land 
modifies  currents ;  elevations  induce  precipitation  ;  in  general, 
land  produces  extremes,  c.  Water  ameliorates  conditions; 
produces  insular  climate. 

2.  Fertility  and  Sterility,  a.  Forests;  distribution 
influenced  by  access  of  moist  Trade  Winds,  b.  Deserts; 
occur  in  regions,  mainly  in  interior,  exposed  to  west  drying 
winds,  c.  Prairies ;  more  or  less  of  desert  character,  but 
probably  often  of  different  origin ;  artificial. 

3.  Isotherms,  a.  Irregular  lines,  tending  towards  north 
in  passing  westward  over  land,  bearing  parallelwise  southwest 
through  ocean,  b.  Deflected  southward  in  interior  of  conti- 
nent, but  irregularly,  varying  with  season  and  modified  by 
topography. 

4.  Isobars,  a.  More  regular  than  Isotherms,  often  con- 
centrically disposed  in  ellipsoids  transverse  to  Isotherms. 

5.  Review  of  U.  S.  Weather  Reports;  general  conclu- 
sions. 

Ref.  : — Works  on  Meteorology;  R.  1  (pp.  43- 
46),  4-8,  11,  18-21,  22,  23. 

1  Atmospheric  currents  are  named  according  to  direction  from  which  they  flow ;  thus 
an  eastern  current  flows  westward,  and  vice  versa. 


io  GENERAL  GEOLOGY. 

DIVISION  F.— LIFE  ON  THE  GLOBE. 

A.    DISTRIBUTION  OF  PLANTS. 

i.  Latitude  and  Altitude  ;  comparative  effects,  a.  i° 
Lat.  from  equator  equivalent  to  ioo  ft.  to  175  ft.  elevation,  with- 
in limits  fixed  by  special  climatic  conditions,  b.  Zones  of  Veg- 
etation :  I.  Polar  (88°  to  780) ;  Alpine  Plants;  at  equator, 
14,170  ft.  II.  Arctic  (780  to  66°);  Dwarf  Willow  and  Alder, 
Rhododendrons;  12,150  ft.  III.  Sub-Arctic  (66°  to  580) ; 
Pines  (ConifercB.) ;  10,140  ft.  IV.  Cold  Temperate  (5 8°  to  450) ; 
Deciduous  Trees;  8,100  ft.  V.  Warm  Tempo-ate  (450  to  340) ; 
Evergreens  (Dicotyl.) ;  6,120  ft.  VI.  Sub- Tropical  (340  to 
230);  Myrtle  and  Laurel;  4,050  ft.  VII.  Tropical  (230  to 
150);  Figs  and  Tree  Ferns;  2,020  ft.  VIII.  Equatorial 
(150  to  o°);  Palms  and  Bananas;  down  to  sea-level  at  equa- 
tor. 

2.  Special  Features,  a.  Retardation  of  flora  of  E. 
Asia.  b.  Local  distribution;  peculiar  cases,  c.  Co/if ervce, 
etc.,  in  hot  springs. 

B.    DISTRIBUTION  OF  LOWER  ANIMALS. 

i.  Sporadic  Origin,  etc.  a.  Specific  Centres,  b. 
Generic  Centres,  c.  Predominant  Animals :  Europe  and  Asia, 
Ruminants;  Africa,  Land  Tortoises ;  N.  Amer.,  Birds  of  Fas- 
Cige;  S.  Amer.,  Edentates  ?-  Australia,  Marsupials,  d.  Repre- 
sentative Species :  camel  and  llama — lion  and  puma — ostrich 
and  emu — crocodile,  gavial,  alligator,  e.  Transferred  species ; 
limit  of  distribution.  Dog  the  only  animal  universally  domes- 
ticated, f.  Zoological  Provinces  [R.  25,  1864],  (Wallace  and 
Sclater):  I.  IVeo- Tropical— S.  A.,  Mex.,  W.  Indies.  II.  Ne- 
arctic — Central  Amer.,  U.  S.,  Canada.  III.  Palcearctic — 
Europe,  N.  Asia  to  Japan,  Africa  N.  of  Desert.  IV.  Ethio- 
pian— Central  and  S.  Africa,  Madagascar.  V.  Lndian — S. 
Asia,  W.  half  of  Malay  Arch.  VI.  Australian — E.  half  of 
Malay  Arch.,  Australia,  Pacific  Is.  (mainly),  g.  Zones  of 
Depth  (Forbes) :  I.  Littoral — bet.  high  and  low  tides.  II. 
Circum-Littoral  (Laminarian) — low  water  to  90  ft.  III.  Me- 
dian [Coralline) — 15  fathoms  (go  ft.)  to  50  fath.  IV.  Ln/ra- 
Median  [Deep-Sea  Coral) — 50-300  fath.  V.  Abyssal — below 
300  fath.  (to  2500  fath.,  or  more). 

2.  Special  Features,  a.  Peculiarities  of  insular  faunae. 
b.  Australian  retardation,  c.  Remarkable  fauna  in  Yellow- 
stone Park.  d.  Mammoth  Cave  fauna,  e.  Deep-Sea  fauna 
[R. : — W.  B.  Carpenter,  in  26,  (vols,  xviii,  xix);  28,  etc.] 


I 


- 


PHYSIO  GRAPHY.  1 1 

C— DISTRIBUTION  OF  MAN. 

i.  Races  and  Minor  Groups.  I.  Indo-European  or 
Caucasian,  (i)  Teutonic.  (2)  Celtic.  (3)  Sclavonic.  (4) 
Circassian.  (5)  Persian.  (6)  Arab.  (7)  Hindoo.  Hab.  : 
S.W.  Asia,  Africa,  nearly  all  of  Europe,  N.  A.,  S.  A.,  Austr., 
etc. ;  500,000,000.  Most  refined  ;  features  regular ;  ample 
hair  and  beard ;  complexion  fair;  white.  II.  Mongolian.  A. 
Mongolian  proper.  (1)  Japanese.  (2)  Chinese.  (3)  Siam- 
ese. (4)  Burmese.  (5)  Turks.  (6)  Tartars.  (7)  Thibetans. 
(8)  Siberians.  (9)  Finns.  (10)  Lapps.  (n)  Esquimaux. 
Hab. :  E.  and  Cent.  Asia  and  Arctic  sea-border;  490,000,000. 
Civilization  heretofore  almost  stationary,  now  progressive. 
Head  square,  face  broad,  high  cheek-bones,  oblique  eyes. 
B.  American,  (i)  S.  A.  Indians.  (2)  N.  A.  Indians;  16,- 
000,000.  Stationary  or  retrograding.  Copper-colored,  hair 
black,  nose  aquiline.  C.  Malay,  (i)  Malays  proper.  (2) 
Papuans.  Hab. :  Malaysia,  Polynesia,  Australasia  ;  Papuans 
confined  to  Australia,  New  Guinea,  New  Hebrides  and  Feejee 
Islands.  (3)  Maoris,  New  Zealand;  60,000,000  (without  Pap- 
uans, which  are  almost  negroes).  Brown.  Papuans  lowest 
in  scale  of  humanity.  III.  Ethiopian  or  Negro.  Branches: 
Gallas,  Nubians,  and  Copts  of  Nile,  Caffres  and  Hottentots 
(who  are  more  properly  Mongolian).  Hab. :  Africa,  S.  of  Sa- 
hara, United  States,  West  Indies  and  Brazil ;  with  Papuans, 
100,000,000.  Lowest  race;  black;  skull  narrow,  forehead  re- 
treating, high  cheek-bones,  thick  lips,  broad,  flat  nose,  project- 
ing chin;  hair  short  and  woolly. 

2.  Population  of  Globe. 

Av.  per 

Density  per  square  mile. 

China,  288    Greenland,  -p^j 

Japan,  233    Patagonia,  Tfor 

Brit.  Islands,  245    Bas.  of  Amazon,        -fa 
Belgium,         438    Iceland,  etc.,  1.88 

Bermuda,        477    Massachusetts,   157.00 
Netherlands,  275    United  States,      II. 3 


Population.      sq.  mi 

Europe,  282,000,000  73 

Asia,  711,000,000  40 

Africa,  130,000,000  11 

N.  America,    50,000,000      6 
S.  America,     22,000,000       2>Yz 
Oceanica,  20,000,000       £,y2 

(According  to  McTurk). 


Ref. :— 1  (p.  609),  2  (p.  479  el  sea.),  3  (p.  155),  4, 
5,  6,  8,  11,  14,  15,  16,  17,  24. 


liST  Several  topics,  which  naturally  fall  under  the  head  of  Physiography 
(such  as  the  general  character  and  distribution  of  earthquakes,  volcanoes, 
hot  springs,  coral  reefs,  etc.),  are  omitted  at  this  point  for  convenience  of 
discussion  later  in  the  course.  Some  few  other  subjects  are  ignored  on 
account  of  their  slight  importance,  geologically  considered. 


12  GENERAL  GEOLOGY. 

PART  III.-GEOGNOSY. 

I.  Definitions,  a.  Geognosy;  the  study  of  earth's  struct- 
ure. A.  Lithology,  study  of  textural  features  (hand  spec- 
imens). B.  Petrology,  structural  arrangement  (in  the  field). 
b.  Mineral ;  inorganic  body,  with  (theoretically)  definite  form 
and  composition,     c.  Rock  ;  aggregation  of  mineral  particles. 

SECTION  L— LITHOLOGY  (Petrography,  Germ). 

DIVISION  A.-CHEMICAL  ELEMENTS. 

i.  Elements  Most  Abundant  in  Rocks.  Only  20  (of 
6$  or  64)  important  as  rock  constituents,  and  only  12  occui 
commonly,  as  below:  I.  Oxygen,  a.  Most  abundant,  com- 
prising ^  (by  weight)  of  earth's  crust.  Oxides,  therefore,  are 
the  most  abundant  compounds,  b.  Combines  readily  with  all 
elements  but  Fl.  c.  Quartz  and  gypsum  more  than  }  O.  d. 
Comprises  .43  of  11  most  common  minerals,  e.  .23  of  atmos- 
phere, and  .89  of  H20.  f.  -I  of  whole  is  combined  with  Si. 
(See  II,  c).  II.  Silicon,  a.  About  {-  of  weight  of  crust,  b. 
Found  only  in  combination  with  0,  from  which  follow  I,  f,  and 
II,  c.  c.  Combined  with  O  (Silica),  ^  weight  of  crust,  d. 
Compounds  hard  and  durable.  e.  Rock  compounds,  with 
some  exceptions,  insol.  in  water.  III.  Aluminium,  a.  About 
iV  weight  of  crust,  b.  Its  oxide  (Alumina),  most  common 
base  in  silicates  and  siliceous  minerals,  c.  Rock  compound? 
(except  sulphate)  insol.  in  water.  IV.  Calcium,  a.  Les? 
than  TV  of  crust,  b.  Found  in  various  silicates,  also  as  Carb. 
and  Sulph.  c.  Rock  compounds  insol.  or  sparingly  sol.  in 
water.  V.  Magnesium,  a.  As  Oxide  (Magnesia)  forms  es- 
sential base  of  durable  silicates,  hard  and  soft.  b.  Rock  com- 
pounds, some  sol.,  some  insol.  in  water.  VI  and  VII.  Potas- 
sium and  Sodium,  a.  Common,  but  less  abundant  than  pre 
ceding,  b.  Oxides  (Potassa  and  Soda),  important  aids  to 
fusion  and  solution  of  silica,  c.  Compounds  more  or  less  sol. 
in  water,  with  few  exceptions.  VIII.  Iron.  a.  Most  widely 
distributed;  native  in  meteorites,  b.  Important  agent  in  color- 
ing and  disintegrating  rocks,  c.  Insol.  and  sol.  rock  com- 
pounds (water).  IX.  Carbon,  a.  Widely  disseminated;  na- 
tive (free)  in  coal,  graphite,  diamond,  b.  Prominent  as  life- 
supporter  and  as  vehicle  of  change,      c.  Rock  compounds 


GEOGNOSY— LITHOLOGY.  13 

generally  insol.  (except  C02  and  alkaline  carbonates).  X. 
Sulphur.  a.  Native  in  volcanic  regions ;  small  quantities 
elsewhere,  b.  As  sulphide  in  ores  of  various  metals,  c.  As 
sulphate  in  gypsum,  etc.  d.  Rock  compounds,  some  sol., 
some  insol.  in  water.  XI.  Hydrogen,  a.  Abundant  as  con- 
stituent of  H20  and  many  other  minerals,  b.  Ingredient  of 
all  organic  compounds.  XII.  Chlorine,  a.  Most  abundant 
in  common  salt.  b.  Compounds  soluble  in  water,  as  a  rule. 
Ref. : — 1  (p.  48),  10  (Part  II);  general  works 
on  chemistry. 

DIVISION  B.— MINERALS. 

1.  Scale  of  Hardness  (Mobs).  (1)  Talc.  (2)  Gypsum. 
(3)  Calcite.  (4)  Fluorite.  (5)  Apatite.  (6)  Orthoclase.  (7) 
Quartz.     (8)  Topaz.     (9)  Corundum.     (10)  Diamond. 

2.  Principal  Rock-forming  Minerals.  Of  1000  spe- 
cies, 350  are  of  some  geological  interest,  40  are  common  as 
rock  constituents,  while  12  make  up  bulk  of  earth's  crust,  viz. : 
I.  Quartz,  a.  Primary  form,  rhombohedron,  but  of  different 
shapes — often  elongated — commonly  hexagonal  prism  termin- 
ated by  6-sided  pyramids;  H.  7;  Gr.  2.5-2.8;  insol.  and 
infus.  (except  with  alkali) ;  no  cl. ;  colorless  to  black,  trans- 
parent to  opaque,  b.  Most  abundant  mineral;  more  than  40 
var.,  including  clear  (or  limpid),  amethyst  (violet),  chalcedony 
(translucent),  agate  (banded  in  colors),  homstone,  jasper,  etc. 
c.  Comp.,  Si02  (silica).  II.  Feldspar,  a.  Cryst.  oblique;  2 
cl.  at  or  near  right  angle;  surface  lustrous;  white,  flesh-red, 
etc.;  H.  6-7;  Gr.  2.85;  difficultly  fusible,  b.  Very  abun- 
dant, 6  recognized  forms  equivalent  almost  to  separate  species. 
C.  Comp.,  alumina  silicate,  each  species  containing  a  charac- 
teristic base  or  two  of  alkali  or  alkaline  earth,  as  K20  (ortho- 
clase), NaO  (albite),  CaO  (anorthite),  Na20  and  CaO  (oligo- 
clase),  CaO  and  Na20  (labradorite).  III.  Mica.  a.  Elastic 
folia;  cl.  basal;  lustre  brilliant;  colorless  to  brown,  etc.,  and 
black,  b.  Abundant  in  granyte;  8  prominent  species,  c. 
Comp.,  alumina  silicate,  with  K20  (muscovite),  MgO  (phlogo- 
pite  and  biotite),  Li20  (lepidolite),  etc.  IV.  Amphibole.  a. 
Oblique,  prismatic  crystals,  sometimes  truncated  so  as  to  ap- 
proach regular  hexagonal  prism;  also  in  long,  thin  crystals  and 
in  bundles  imbedded  in  rock,  as  well  as  in  short,  stout  crys- 
tals ;  cl.  parallel  to  faces ;  black,  green,  white,  brownish  and 
intermediate  shades,     b.  Forms  as  follows:    (1)  Dark  green 


i4  GENERAL  GEOLOGY. 

to  black,  stout  crystals  {hornblende) ;  (2)  long,  green  prisms  or 
fibrous  (actinolite) ;  (3)  grayish  and  brownish  green,  fibrous  or 
acicular  (ant hop  hy  I  lite) ;  (4)  long,  white  prisms  or  fibrous  (trem- 
olite) ;  (5)  delicate,  flexible  fibres  (asbestos) ;  (6)  also  in  dissem- 
inated grains  in  rocks,  c.  Comp.,  Si02,  MgO,  CaO,  FeO, 
and,  occasionally,  A1203  and  MnO.  V.  Pyroxene,  a.  Cryst. 
oblique,  prismatic,  nearly  square  in  cross-section,  often  becom- 
ing 8-sided  prism  by  replacement  of  edges;  cl.  as  in  amphi- 
bole,  and  color  similar;  H.  5-6;  Gr.  3.23-3.5.  b.  Var.,  (1) 
massive,  cleavable,  grayish-green  (sahlite) ;  (2)  thin,  foliated, 
brownish  -green  or  bronzen  (hypersthene) ,  grass-green  (diallage); 
(3)  common,  black,  etc.  (ai/gite).  c.  Comp.,  very  near  am- 
phibole.  VI.  Chrysolite  (not  chrysotile).  a.  In  grains,  masses 
and  rectangular  crystals ;  glassy,  pale  or  dark  green  (olivine) ; 
H.  nearly  that  of  quartz  (7).  b.  Common  in  volcanic  rocks; 
olivine  characteristic  of  basalt  and  other  crystalline  rocks,  c. 
Comp.,  magnesia  silicate,  often  with  considerable  FeO.  VII. 
Chlorite,  a.  Resembles  mica,  but  folia  not  elastic  ;  also  mass- 
ive with  granular  texture ;  color  olive-green,  rarely  approach- 
ing white ;  H.  2.5,  easily  cut  with  knife,  b.  Ingredient  of 
many  schists.  c.  Comp.,  typical,  MgFeSi04,  with  varying 
proportions  of  base,  and  considerable  water;  also  var.  with 
AI2O3.  VIII.  Talc.  a.  Foliaceous  or  compact  and  massive ; 
folia  7iot  elastic ;  color  light  to  dark  green  and  brownish  ;  H.  1 ; 
greasy  to  touch,  b.  Var.,  (1)  common  as  above;  (2)  granu- 
lar or  compact  (steatite,  soap-stone),  c.  Comp.,  MgSi03,  with 
water;  Si02  62.12,  MgO  32.94,  H2O  4.94  =  100.  IX.  Ser- 
pentine, a.  Usually  massive,  without  cl.,  sometimes  prismatic ; 
delicately  fibrous  var.  (amianthus,  chrysotile).  b.  Abundant 
as  rock  under  certain  circumstances.  c.  Comp.,  MgSi03, 
with  water;  Si02  43.6,  MgO  43.4,  H20  13.0  =  100.  X.  Cal- 
cite.  a.  Hexagonal,  usually  with  perfect  rhombohedral  cl. ; 
color  white,  yellow,  reddish  or  even  black ;  effervesces  with 
acid;  H.  3,  easily  scratched  with  knife;  Gr.  2.69-2.75.  b. 
Principal  ingredient  of  large  proportion  of  limestones  and  of 
all  true  marbles,  as  well  as  chief  constituent  of  marls  and  hy- 
draulic limestones,  c.  Comp.,  CaC03;  C02  44.0,  CaO  56.0 
=  100.  XI.  Dolomite,  a.  Resembles  calcite  in  form,  but 
differs  slightly  in  interfacial  angles  (1060  15';  bet.  calcite 
1050  5',  and  magnesite  [MgCo3]  1070  25') ;  darker  colors  pre- 
dominate; no  effervescence  unless  heated;  H.  3.5-4.5;  Gr. 
2.88-2.95.  b.  Occurs  in  many  so-called  limestones,  and  in- 
directly yields   serpentine   under   certain   circumstances,     c. 


GE  0  GNOS  Y—LITHOL  OGY.  15 

Comp.,  normal,  CaC03  54.3  per  cent.,  MgC03  45.7  per  cent. 
XII.  Gypsum,  a.  Oblique  prisms  ;  cl.  very  perfect  in  one  di- 
rection, affording  non-elastic  plates;  also  massive,  compact, 
etc.;  white  to  dark,  transparent  to  opaque;  H.  1.5-2  ;  affords 
"  Plaster  of  Paris  "  on  heating,  b.  Abundant  in  various  forms  ; 
var.,  (1)  selenite,  transparent,  basal  cl. ;  (2)  satin  spar,  fine 
fibrous ;  (3)  alabaster,  compact  or  saccharoidal.  c.  Comp. 
CaS04,  2H2O.  XIII.  Iron  Ores,  I.  Magnetite,  a.  Cryst. 
octahedral,  etc.  ;  also  found  granular,  compact,  earthy,  or  as 
fine  sand  ;  black,  with  metallic  lustre,  giving  black  streak  and 
powder,  b.  In  beds  and  veins,  also  in  grains  disseminated 
through  crystalline  rocks,  c.  Comp.,  Fe304  (ferroso-ferric  ox- 
ide). II.  Haematite  {Hematite,  specular  iron).  a.  Cryst. 
hexagonal,  often  micaceous,  also  massive,  compact,  earthy, 
fibrous,  etc. ;  lustre  dull  to  sub-metallic  and  metallic;  blood-red 
streak  and  powder,  b.  In  beds  and  veins  and  variously  dis- 
tributed through  other  rocks ;  var.,  specular  iron,  lustre  metal- 
lic, crystallized ;  red  ochre,  soft ;  red  chalk,  with  clay.  c. 
Comp.,  Fe203  (ferric  oxide,  iron  sesquioxide,  iron  peroxide). 

III.  Limonite  [Brown  Hematite),  a.  Cryst.  indistinct,  mam- 
millaiy,  botryoidal,  stalactitic,  fibrous,  massive  and  earthy; 
lemon-yellow  streak  and  powder,  b.  In  beds,  etc.,  of  later 
date  than  preceding,  now  forming  in  bogs  and  by  oxidation  of 
pyrites  and  iron  carbonates ;  bog  iron  ore  and  yellow  ochre 
prominent  var.     c.   Comp.,  2Fe203+3H20  (orthic  hydrate). 

IV.  Pyrite.  a.  Cryst.,  cubes,  octahedrons,  etc. ;  brassy  to 
black,  b.  Var.,  several,  c.  Comp.  (common),  FeS2.  XIV. 
Graphite  {Plumbago,  wrongly  Black  Lead),  a.  Crystallized 
and  amorphous,  commonly  latter;  lustre  rather  metallic,  streak 
black  (used  for  lead  pencils),  b.  Occurs  in  lumps  and  nests; 
results  from  transformation  of  anthracite,  c.  Comp.,  C  only, 
when  pure. 

Ref. : — 1  (p.  52),  2  (chap.  hi).  9,  10  (Part  II), 
29-31,  34. 


©IVIS30N  C.-OBGAMC  CONSTITUENTS. 

I.  Siliceous,  a.  Spicula  of  sponges,  b.  Remains  of 
Diatomacea;,  Polycystinae,  etc.  c.  Silicified  shells  and  wood 
produced  by  action  of  siliceous  waters,  d.  Infusorial  remains. 
e.  Products:  bog  iron  ore  (in  part),  infusorial  earths  (Tripoli 
polishing  slate,  etc.),  flint,  opal  (to  some  extent),  etc. 


16  GENERAL  GEOLOGY. 

2.  Calcareous,     a.  Various  shells  (calcite  and  aragonite). 

b.  Spines  of  Echini,  c.  Foraminiferal  remains,  d.  Ccenen- 
chyma  of  corals,  e.  Crinoidal  columns,  f.  Skeletons  of 
Crustacea,  g.  Some  plant  remains  (corallines),  h.  Products : 
Marl,  limestones,  white  chalk,  coral  reefs,  etc. 

3.  Carbonaceous,  a.  Plant  remains  in  general,  b. 
Some  animal  remains  under  peculiar  conditions,  c.  Products  : 
Peat,  lignite,  jet,  coals,  anthracite,  petroleum,  asphalte,  graphite, 
resins,  etc.,  diamond  (?). 

4.  Phosphatic.  a.  Bones  of  Vertebrata.  b.  Scales  of 
fishes,  etc.  c.  Enamel  of  teeth,  d.  Shells  of  Lingula  and 
allied  genera  of  Mollusks.  e.  Products:  Deposits  of  guano, 
phosphatic  nodules,  bone-breccias,  etc. 

Ref. :— 1  (Part  II),  2  (p.  382),  3  (p.  153),  10 
(Part  II),  35  (p.  327),  36  (pp.  22,  105,  etc.), 
37  (PP-  462,  759). 

DIVISION  ».— CONCERNING  ROCKS. 

A.— GENERAL  CHARACTER. 

1.  Texture  of  Rocks,  a.  Homogeneous  or  heteroge- 
neous, b.  Var. :  (1)  crystalline;  (2)  granular,  with  rounded 
grains;  (3)  crystalline-granular,  crystalline  grains;  (4)  crypto- 
crystalline  (compact) ;  (5)  earthy  ;  (6)  friable,  readily  crumbled 
in  fingers;  (7)  glassy  or  vitreous ;  (8)  slaggy  ;  (9)  schistose,  di- 
vided by  alternating  mineral  layers;  (10)  foliated ;  (n)  por- 
phyriiic,  with  distinct  disseminated  crystals  in  homogeneous 
base;  (12)  vesicular,  drawn  out  so  as  to  produce  numerous 
cavities  ;  (13)  amygdaloidal,  with  almond-shaped  cavities,  com- 
monly filled  with  foreign  minerals. 

2.  Difficulties  in  Rock  Study,  a.  Close  gradations 
existing  among  rocks,  b.  Similarity  of  certain  minerals  in 
form  or  composition,  c.  Fineness  of  texture  in  some  rocks. 
d.  Want  of  ready  means  of  ascertaining  all  components. 

B.— DETERMINATION  AND  CLASSIFICATION. 

1.  Determination  of  Rocks,  a.  General  value  of 
texture,    b.  Value  of  chemical  analysis,  and  its  disadvantages.  ^ 

c.  Microscopic  analysis,  its  uses  and  abuses,  d.  Electro- 
magnet as  accessory  instrument. 

2.  Classification  of  Rocks,  a.  System  of  Zirkel,  based 
on  species  of  feldspar,     b.  System  of  Durocher  and  Bunsen, 


GEOGNOSY— LITHOLOG  Y 


i7 


proportions  of  silica,     c.  Convenient  system  for  general  pur- 
poses, prepared  by  Theo.  B.  Comstock  [R.  33].  based  on 

3.  Scheme  of  Classification. 

/.   SERIES,  representing  mode  of  origin  (Genesis). 

II.  CLASS,  representing  genetic  conditions  (Environment). 

III.  Division,  representing  secondary  environment  (Position). 

IV.  Family,  representing  dominant  i7igredient  (Structure). 

V.  sub-family,  representing  condition  of  mass  (Character). 

VI.  Genus,  representing  mineral  association  (Type). 

VII.  Species,  indicating  special mineral combination  (Quality). 

VIII.  Variety,  indicating  textural  modification  (Texture). 

4.  Systematic    Arrangement   of    Most    Common 
Rocks. 


SERIES  I. 
CLASS  I.— 

Fam.  A. — Feldspathic. 

Gen,  1.  Graityte  (quartz,  feld- 
spar, mica). 

Gen.  2.  Protogine  (quartz,  feld- 
spar, talc). 

Gen.  3.  Granytine  (quartz, 
feldspar). 

CLASS  II.- 

DlVISION   I.' 

Fam.  A. — Feldspathic. 

SUB-FAM.   I. CRYSTALLINE. 

Gen.  1.  Porphyrine  (basic  feld- 
spar). 

Gen.  2.  Felsyte  (acidic  feld- 
spar, quartz  occasional). 

Gen.  3.  Mica-trap  (feldspar, 
mica). 

SUB-FAM.  2. FRAGMENTAL. 

Gen.  1.  Felsytic. 
"     2.  Porphyritoid. 

Division  2. 
Fam.  A.— Trachytic  (Acidic). 

SUB-FAM.   I. CRYSTALLINE. 

Gen.  1.  Trachyte  (acidic  feld- 
spar, mainly). 


IGNEOUS. 

GRANYTIC. 

Fam.  B. — Hornblendic. 
Gen.  1.   Syenyte  (quartz,   feld- 
spar, amphibole). 


ERUPTIVE. 

— Trappean. 

Fam.  B. — Pyroxenic. 

SUB-FAM.    I. CRYSTALLINE. 

Gen.  1.  Dioryte  (feldspar  and 
hornblende;  no labradorite). 

Gen.  2.  Melaphyrine  (basic 
feldspar  and  pyroxene). 


SUB-FAM.  2. FRAGMENTAL. 

Gen.  1.  Diorytic. 
"     2.  Melaphyroid. 

-Volcanic. 
Fam.  B. — Basaltic  (Basic). 

SUB-FAM.   I. CRYSTALLINE. 

Gen.  1.    Basalt     (labradorite, 
augite,  olivine,  menaccanite). 


i8 


GENERAL  GEOLOGY. 


Gen.  2.  Trachoryte  (acidic  feld- 
spar, etc.,  and  hornblende). 

Gen.  3.  Phonolyte  (glassy  feld- 
spar, nephelite,  hornblende). 

SUB-FAM.  2. FRAGMENTAL. 

Genera  dependent  upon  com- 
position ;  made  up  of  ingre- 
dients of  Trachytic  char- 
acter. 


Gen.  2.  Amphigenyte,  or  Leii- 
citophyr  (labradorite  and  leu- 
cite).     Lava  of  Vesuvius. 

Gen.  3.  Nephefaiyte  (nephelite, 
augite,  magnetite). 

SUB-FAM.   2. FRAGMENTAL. 

Genera  dependent  upon  com- 
position ;  made  up  of  ingre- 
dients of  Basaltic  charac- 
ter. 


SERIES  IL—METAMORPHIO 
CLASS  I.— HYPOGENIC. 


Fam.  A. — Micaceous. 
Gen.  1.   Granyte  (same  as  7, 1, 

A,  1). 
Gen.  2.    Mica-schist        (mica, 

quartz,  often  feldspar). 

Fam.  C. — Feldspathic. 
Gen.  1 .  Felsyte  (practically  the 

same  as  I,  II,  A,  1,  2). 
Gen.  2.    Euphotide     (feldspar, 

diallage). 


Fam.  B. — Hornblendic. 
Gen.  1.     Syenytine      (includes 
here  syenytic   forms   which 
would  be  separated  in  more 
detailed  classifications. 

Fam.  D. — Hydrous  Mag- 

NESIAN. 

Gen.  1.  Talcose  (type,  talc 
schist). 

Gen.  2.  Serpentinous  (type,  ser- 
pentine). 

Gen.  3.  Chloritic  (type,  chlo- 
rite schist). 


CLASS  II.— METAMERIC. 


Fam.  A. — Quartzose. 
Gen.  1.   Qiiartzyte. 

Fam.  C. — Calcareous. 

Gen.  1.  Calciferous  (altered 
calcite). 

Gen.  2.  Dolomyiic  (altered  dol- 
omite). 

Gen.  3.  Gypsiferous  (altered 
gypsum). 


-Ferrous. 

-  (includes  iron 


Fam.  B.- 
Gen.  1.  

ores). 

Fam.  D. — Argillaceous. 
Gen.  1.  Argyllyte  (altered  clay). 

Fam.  E. — Carbonaceous. 
(Anthracite,  graphite,  etc.) 


1  The  sub-families  of  SERIES  II  are  omitted  here,  being  of  no  special  import- 
ance tc  the  general  student. 


GEOGNOSY— PETROLOGY.  19 

SERIES  III.— AQUEOUS} 
CLASS  I.— MECHANICAL. 

Comprises  deposits  formed  by  action  of  water  on  land,  as 
sand,  mud,  gravel,  etc.,  and  their  consolidated  forms,  as  sand- 
stone, shale,  conglomerate. 

CLASS  II.— CHEMICAL. 

Includes  accumulations  as  precipitates  and  other  results  of 
chemical  action  in  nature,  as  some  limestones,  geyserite,  stalac- 
tite, etc. 

CLASS  III.— ORGANICAL. 

All  natural  collections  of  material  directly  formed  by  the  ac- 
tion of  plants  or  animals,  or  by  their  decay,  are  to  be  regarded 
as  belonging  to  this  group,  as  peat,  coal,  petroleum,  some  marls, 
guano,  phosphate  beds,  etc. 

Ref. : — 1  (Part  II),  2  (chaps,  iv,  v),  3  (parts  of 
chaps,  ii,  iii,  iv),  9,  10  (Part  II),  29,  32,  33, 
47- 


N.B. — It  is  impossible  to  give  this  portion  of  the  lectures  in  full  within 
reasonable  limits.  As  additional  aids,  students  who  desire  to  do  so  can 
procure  copies  of  R.  32  (price  io  cts.)  and  R.  33  (price  40  cts.)  at  the 
Geological  Laboratory,  but  this  is  not  necessary. 


SECTION  II -PETROLOGY  (Structural  Geology). 

DIVISION  A.-GE^EEAL  STRUCTURE  OF 
EARTH. 

1.  Form  of  Earth,  a.  Oblate  spheroid,  or  spheroid  of 
rotation,  b.  Polar  diam.  =  7899.60  statute  miles;  equatorial 
diam.  =  7926.05  miles  (M.  Bessel).  c.  Nearly  all  of  "relief" 
of  globe  lies  within  an  exterior  protuberance  beyond  the 
sphere  having  polar  diam.     d.  Axis  probably  stable. 

2.  Density  of  Earth,  a.  Mean  Gr.  bet.  5  and  6,  as 
shown  by:  (1)  Experiments  of  Ordnance  Surv.,  Gt.  Brit.  (Col. 
Sir  H.  James),  on  deflection  of  plumb-line  [R.  39,  1856,  vol. 

1  For  the  purposes  of  this  Course  it  is  not  necessary  to  classify  the  members  of  SE- 
RIES III  as  fully  as  the  preceding.  In  the  lectures  on  Economic  Geology  considera- 
ble attention  is  given  to  these  details. 


2o  GENERAL  GEOLOGY. 

cxlvi,  p.  591];  (2)  difference  in  times  of  oscillation  of  pendu 
lums  at  top  and  bottom  of  deep  mines  [R.  39,  vol.  cxlvi,  1856, 
P-  355]  5  (3)  Hutton's  observations  of  local  attraction  at  1000 
points  on  Mt.  Schehallien,  Scotland  [R.  39  (1821,  p.  276)]; 
(4)  Cavendish's  experiments  (1798),  with  Michell's  apparatus 
(torsion  balance),  comparing  earth's  attraction  with  that  of 
mass  of  lead;  (5)  Bailey's  similar  experiments  in  1842  (mean 
Gr.  5.6604)  [R.  40,  p.  69].  b.  Gr.  of  heaviest  rock-masses 
(as  basalt)  only  3.0;  hence — c.  Interior  of  earth  much  heav- 
ier than  at  surface;  estimated  at  16.27  [R-  4X>  v°l-  iy>  P-  33\ 

Gravity  should  increase  wt.  rapidly  within,  but  if  homogeneous,  even 
granyte  (Gr.  2.5)  would  become  heavier  than  5  or  6  long  before  reaching 
centre;  air  (Gr.  =.0012+)  would  have  density  of  water  at  34  miles, 
water  density  of  iron  at  200  miles,  iron  density  of  platinum  at  175  miles, 
and  even  cork  (Gr.  0.24)  would  have  Gr.  at  centre  of  earth  equal  to  twenty 
times  earth's  mean  density. 

3.  Interior  of  Earth,  a.  Seat  of  expansive  agent:  (1) 
follows  from  preceding;  (2)  also  proven  by  temp,  of  deep 
wells  and  mines;  average  increase  of  i°F.  for  each  55  ft.  of 
descent  after  first  100  ft.  b.  Internal  fluidity  doubtful  and 
improbable,  though  still  believed  by  some  geologists,  c. 
More  or  less  local  seas  of  molten  material  as  shown  by :  (1)  act- 
ive volcanoes ;  (2)  old  fissure  eruptions,  d.  Probably  more  or 
less  of  "honeycomb"  structure,  e.  Sir  Wm.  Thomson's  views 
regarding  solidity  of  earth  [R.  42  (xxiii,  157)543  (xiv,  426),  13 
(xii,  336,  1876)];  M.  Delaunay  [R.  44  (v,  507),  45  (Oct., 
1867)];  Pratt  [R.  26,  1870];  Hopkins  [R.  39,  1839,  and  Brit. 
Assoc.  Rep't,  1847];  D.  Forbes  [R.  44  (iv),  45  (Oct.,  1867)]; 
T.  S.  Hunt  [R.  45  (xx,  315)].  f.  Composition  of  deep-seated 
material  dolerytic  (iron  bearing) ;  Conn,  trap  ridges,  g.  Hints 
from  comp.  of  meteors. 

4.  Crust  of  Earth.  a.  Present  application  of  term 
"crust."  b.  Sources  of  knowledge :  (1)  Mines,  wells,  borings; 
(2)  exposures  in  cliffs,  gorges,  canons,  etc.;  (3)  tilted  rocks. 
c.  Known  thickness  5  mi.  (aver.)  to  20  mi.  (max.) 

5.  Relations  of  Form  to  Structure,  a.  Original  form 
commonly  structural;  Ex. :  mountain  folds,  volcanic  cones,  etc. 
b.  Secondary  action  often  obscures  structure ;  Ex.:  valley  be- 
coming mountain  by  erosion,  depressed  fold  filled  with  detritius. 

Ref. : — 1   (p.  736),  2  (chap,  xvi),  3  (Part  II, 
chap,  i,  p.  164),  10,  41. 

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U    *  ^l> dL^-^JJ^-^  , ,  / to  -'H^c4„ 


GEOGNOSY— PETROLOGY.  21 

DIVISION  B.— STRUCTURE  OF  ROCK  MASSES. 
A.— GENERAL  ARRANGEMENT. 

i.  Mode  of  Occurrence.  A.  Igneous,  a.  Position:  (i) 
beneath  other  terranes ;  (2)  protruding  as  nuclei  of  various 
mountain  ranges ;  (3)  above  or  between  other  terranes  (inter- 
bedded)  ;  (4)  occupying  fissures  in  other  rocks.  b.  Strictly 
unstratified.  c.  Common  structures:  Massive,  columnar, 
platy.  A.  I.  Granytic.  a.  Position  and  relation  to  Aqueous 
Rocks;  intrusive,  b.  Rarely  cuboidal  or  columnar.  A.  II. 
Trappean.  a.  (1)  Intrusive;  in  sheets,  veins,  dikes,  necks; 
(2)  interbedded.  A.  III.  Volcanic,  a.  Position  chiefly  at 
surface.  B.  Metamorphic.  a.  Beneath  Aqueous  Rocks; 
otherwise  nearly  as  in  C.  b.  Special  structural  features,  as 
cleavage.     C.  Aqueous,     a.  Nearest  surface,     b.  Stratified. 

2.  Unstratified  Terranes.  a.  All  Igneous  rocks,  strictly 
speaking,  b.  Material  filling  fissures  and  intrusive  veins  [see 
B,  4.  Igneous  Dikes],  c.  More  or  less  homogeneous  in  text- 
ure :  crystalline  or  amorphous. 

3.  Stratified  Masses,  a.  Consolidated  sediments  main- 
ly, b.  Aqueous  and  Metamorphic  rocks,  c.  Crystalline  or 
fragmental. 

B.— FEATURES  COMMON  TO  ALL  ROCKS. 

1.  Fissures,  a.  Frequently  miles  in  length,  many  feet 
wide,  of  unknown  depth,  b.  Commonly  in  parallel  series  fol- 
lowing trends  of  mountain  systems,  c.  Also  accompanied  by 
smaller  transverse  systems,  d.  Variously  inclined,  vertical  to 
low  angle. 

2.  Faults,  a.  Non-adjustment  of  two  sides  of  fissures. 
b.  More  apparent  in  stratified  rocks  [see  beyond,  C,  3.  Dislo- 
cations], c.  Very  common  in  mountainous  regions,  often  of 
great  extent  horizontally  (250  miles)  and  vertically  (20,000 
ft.)     d.  "Hade."     e.  "Throw." 

3.  Joints,  a.  Division  planes  in  two  or  more  directions. 
b.  Parallelwise  to  minor  ridges  or  folds,  c.  Courses  vary  ac- 
cording to  character  of  rocks,  producing  blocks  of  different 
shapes  and  sizes : 

In  basalt  and  other  Igneous  rocks,  columnar  or  prismatic ;  in  granyte, 
large,  irregular,  columnar  or  cuboidal ;  in  limestone,  regular,  cubical ;  sand- 
stone, more  or  less  prismatic  (quadrangular) ;  shale,  commonly  rectangu- 
lar ;  in  Metamorphic  rocks,  often  rhomboidal,  small. 

4.  Igneous  Dikes,  a.  Fissures  suddenly  filled  by  Trap- 
pean ejections       b.  Mainly  ancient  choked-up  fissures,      c. 


22  GENERAL  GEOLOGY. 

Occur  in  crystalline  or  amoqjhous  masses,  d.  Offsets  ("  igne- 
ous veins"  and  "cotemporaneous  veins.")  e.  Granyte  dikes 
and  "elvans."     f.  Structural  features  of  dikes  : 

(i)  Traversed  commonly  by  two  series  of  joint-planes  meeting  at  right 
angles;  (2)  often  columnar  (as  basalt)  with  columns  commonly  perpendic- 
ular to  walls  of  dike;  (3)  edges  frequently,  and  inner  portions  occa- 
sionally, streaked  with  tachylite  ;  (4)  selvage  of  decomposed  material  not 
infrequent;   (5)  adjacent  rocks  often  much  altered. 

f.  Necks;  ( 1 )  occupy  throats  of  extinct  volcanoes ;  (2)  crys- 
talline or  fragmental  [R.  44  (iii,  243)]. 

5.  Mineral  Veins,  a.  Fissures,  crevices  or  patches  more 
or  less  filled  by  material  slowly  accumulated,  b.  Extent  and 
direction  dependent  on  size  of  fissure,  c.  Kinds  :  (1)  veins  of 
infiltration,  usually  siliceous  or  calcareous;  (2)  veins  0/ segrega- 
tion, no  definite  walls — same,  in  effect,  as  concretions,  explained 
beyond;  (3)  fissure  veins,  commonly  metalliferous,  d.  Struct- 
ure commonly  banded,  e.  Leaders  and  feeders.  \Full  dis- 
cussion given  i?i  Course  LI, — Economic  Geology]. 

6.  Concretions.  A.  Congenital.  I.  Lgnigenous.  a. 
In  Igneous  rocks;  as  (1)  "druses"  in  granyte;  (2)  spheroids 
in  doleryte  and  dioryte.  b.  In  Metamorphic  rocks  ;  (1)  patches 
of  foreign  or  other  crystals  in  gneiss,  etc.  B.  Secondary. 
a.  In  all  rocks,  but  chiefly  in  Aqueous  [see  D,  1.  Concretions], 

7.  Slaty  Cleavage,  a.  Most  common  in  Metamorphic 
rocks.1 

C— SPECIAL  FEATURES  OF  STRATIFIED  ROCKS. 

i.  Regular  Arrangement,  a.  Planes  of  stratification ; 
use  of  terms  stratum,  formation,  b.  Original  horizontal  posi- 
tion of  beds  proven  by:  (1)  composition  of  beds;  (2)  positions 
of  trees  and  other  entombed  remains,  c.  Inclined  strata,  d. 
"Dip";  measurement  and  sources  of  error,  e.  "Strike";  at 
right  angle  to  dip.     f.  "Conformity."     g.  Association  of  beds. 

2.  Irregular,  or  Secondary  Arrangement,  a.  "Over- 
lap." b.  Foldings:  (1)  major  folds;  (2)  minor  folds;  (3)  con- 
tortions; (4)  plications.  c.  Use  of  terms  anticlinal,  syncli- 
nal, uniclinal,  qua-qua-versal.  d.  "  Unconformity,"  real  and 
apparent,     e.   Inversion  of  strata. 

3.  Dislocations  [see  ante,  B,  2.  Faults],  a.  Kinds:  (1) 
vertical;  (2)  inclined;  (3)  trough;  (4)  step;  (5)  reversed 
(not  common),     b.  Simple  and  compound  faults,     c.  Varia- 

1  The  full  discussion  of  the  subject  of  cleavage  in  rocks  will  be  more  advantageously 
taken  up  under  the  head  of  JE. — Paiticular  Structure  of  Metamorphic  Rocks,  later  in 
the  course. 


^-^^v  ",  V^^jL-JS      ^ 


GEOGNOSY— PETROLOGY.  23 

tions,  due  to  (1)  nature  of  beds;  (2)  inclination  of  beds.  d. 
Faults  in  anticlinals  and  synclinals,  e.  Strike  faults,  etc.  f. 
Distortions,  etc.  g.  Resulting  fissures  and  cavities,  h.  Meth- 
od of  determining  thickness  of  faulted  beds.  i.  Rules  and 
conclusions  : 

( 1 )  Acute  aiigle  very  rarely  occurs  with  surface  of  given  bed  on  both  sides 
of  fault. 

(2)  Hade  is  commonly  in  direction  of  down-throw. 

4.  Lamination,  a.  Planes  of  lamination,  b.  Regular 
lamination.  c.  Oblique  lamination  ("false-bedding").  d. 
"Rolls,"  "swells,"  etc.     e.  Lateral  extent  of  beds  : 

( 1 )  7 lie  finer  the  particles  the  more  extended  and  more  regular  (in  thick- 
ness) the  beds,  and  vice  versa. 

(2)  Limestone  liable  to  extend  farthest,  shale  next,  then  sandstone,  con- 
glomerate  shortest  distance. 

J).— PECULIARITIES  OF  AQUEOUS  ROCKS. 

1.  Concretions,  a.  Really  veins  of  segregation  [ante, 
B,  5,  c,  (2)].  b.  Found  in  all  rocks,  but  especially  charac- 
teristic of  Aqueous,  c.  In  Aqueous  rocks,  always  of  second- 
ary origin,  d.  Forms  of  nodules  :  globular,  lenticular,  annu- 
lar, botryoidal,  and  various,  e.  Hollow,  solid,  honey-combed, 
partitioned,  radiated,  etc.  f.  Often  have  fossil  or  crystal  as 
nucleus,     g.   Comp. : 

(1)  In  sandstone  CaC03,  FeS2  or  F&2O3 ;  (2)  in  shale  CaC03  (septaria), 
FeCOs  (clay  iron-stone),  FeS^  (Catalina  stone) ;  (3)  in  limestone  SiOj 
(chert,  flint,  etc.),  also  in  dolomite;  (4)  dolomite  itself  also  sometimes  nod- 
ular. 

2.  Petrifactions,  a.  Include  remains  of  plants  and  ani- 
mals, generally  hard  parts,  b.  State  of  preservation  varies 
greatly ;  structure  commonly  apparent,  sometimes  only  outline. 
c.  Replacement  (pseudomorphism),     d.  Casts  and  moulds. 

3.  Peculiar  Markings,  a.  Wave  marks,  b.  Ripple 
marks,  c.  Rill  marks,  d.  Rain  prints,  e.  Mud  cracks. 
f.  Traces  left  by  flowing  mud.     g.  Tracks  of  animals. 

E.— PARTICULAR  STRUCTURE  OF  METAMORPHIC 
ROCKS. 

i.  Slaty  Cleavage,  a.  Not  necessarily  confined  to  Met- 
amorphics,  but  more  common  than  in  Aqueous  or  Igneous. 
b.  Divisional  planes  more  or  less  transverse  to  bedding,  c. 
Course  of  planes  parallel  to  main  axes  of  elevation,  d.  Lam- 
ination often  obliterated  by  cleavage  planes,  e.  Planes  often 
extend  through  great  series  of  beds.     f.  Surface  bending  of 


24  GENERAL  GEOLOGY. 

planes,     g.  Sedgwick's  conclusions  [R.  48  (vol.  iii,  On  Struct- 
ure of  Large  Ati?ieral  Masses)] : 

(1)  Strike  of  cleavage  planes  (when  well  developed  and  extending  through 
mountain-masses)  coincides  nearly  with  strike  of  beds. 

(2)  Dip  of  planes  (in  amount  and  direction)  not  affected  by  changes  in 
beds,  even  when  latter  are  contorted. 

2.  Foliation,  a.  Darwin  and  Sharpe  regard  it  as  extreme 
degree  of  slaty  cleavage,  b.  Geikie  considers  it  result  of  met- 
amorphism.  c.  Prof.  Geikie's  view  receives  support  from 
common  direction  of  folia  (coincident  with  bedding). 

Ref. : — 1  (pp.  79-114),  2  (chaps,  vi-xv),  3  (Part 
II,  chaps,  ii-v,  mainly),  9,  10,  47. 


PART  IV -DYNAMICAL  GEOLOGY. 

1.  Scope,  a.  Treats  of  geological  agents  and  their  present 
operations,    b.  Comprises  chiefly  chemical  and  physical  geology. 

2.  Divisions.  I.  Subterranean  Agencies.  II.  Sur- 
face Agencies,  including  Aqueous,  Atmospheric  and  Organic. 
III.  Morphogony,  or  origin  of  surface  outlines. 

SECTION  I -SUBTERRANEAN  AGENCIES. 

1.  Causes  of  Disturbance,  a.  Subject  but  little  under- 
stood, b.  Local  bodies  of  molten  material  within  the  crust. 
C.  Contraction  of  crust,  d.  Access  of  water  through  fissures 
to  heated  caverns  in  interior  mass.  e.  Sir  Humphrey  Davy's 
idea  of  oxidation  of  metallic  bases  of  earths  and  alkalies  [R.  49]. 

2.  General  Effects,  a.  Sudden  movements  of  crust  as 
exhibited  in  earthquakes,    b.  Slow  elevations  and  subsidences. 

c.  Ejection  of  molten  material  through  fissures  and  craters. 

d.  Physical  and  chemical  changes  in  rocks;  as  (1)  expansion; 
(2)  contraction;  (3)  folding;  (4)  slaty  cleavage;  (5)  foliation; 
(6)  concretions;  (7)  mineral  veins,  e.  Phenomena  of  hot 
springs  and  geysers. 

DIVISION  A.— ACTION  OF  HEAT. 

A.— SOURCES  OF  TERRESTRIAL  HEAT. 

i.  Heat  from  Sun,  etc.  a.  Nearly  40  per  cent,  ab- 
sorbed by  atmosphere,     b.  Penetrates  crust  50  to  100  ft."    c. 


SUBTERRANEAN  AGENCIES.  25 

Amount  received  varies;  (1)  with  seasons;  (2)  with  eccentricity 
of  orbit,  d.  Daily  invariable  isogeother?n  but  two  or  three  ft. 
underground,  e.  First  constant  isogeotherm  an  irregular  line  ; 
from  less  than  2  ft.  under  heat  equator  to  more  than  100  ft. 
at  poles — varying  in  submergence  according  to  amount  of  an- 
nual variation,  and  representing  temp,  near  mean  annual  iso- 
therm at  surface,  f.  Heat  from  fixed  stars  very  important, 
nearly  |  of  amount  from  sun. 

2.  Interior  Heat.  a.  Invariably  increases  in  descending 
below  limit  of  surface  action,  b.  Rate  of  increase  varies  ac- 
cording to  locality,  mainly  owing  to  varying  conductivity  of 
rocks,  as  in  table  on  next  page.  c.  Annual  loss  of  heat  not 
great,  owing  to  low  conductivity  of  materials  of  crust ;  Thom- 
son estimates  enough  to  melt  777  cu.  miles  of  ice,  equal  to 
earth-envelope  of  only  .0085  mm. 

3.  Chemical  Action,  a.  Possible  source  of  some  im- 
portance, but  not  easily  estimated,  b.  Result  of  decomposi- 
tion (oxidation). 

4.  Mechanical  Sources,  a.  Movement  in  crust,  chief- 
ly, b.  Mallet's  experiments  [R.  42,  1862  (Paper  on  "Vol- 
canic Energy")],  epitomized  in  following  table: 

Heat  Produced  by  Crushing. 

Z  cu.  ft.  of  crushed  produces  Temp.  {F.)  of  sp.  heat. 

(1)  Syenyte  or  granyte Ilo°.oo-2I30.25 0.181-0.186 

(2)  Slate I32°.85 0.201 

(3)  "     I44°.2Q 0.218 

(4)  Sandstone 32°.84 0.238 

(5)  "         47°-79 0.233 

(6)  "         86°.i3 0.215 

(7)  Limestone  (compact) 20°.o8 0.245 

(8)  "  "        26°.28 0.265 

(9)  Marble  (Devonshire) H4°.68 0.203 

B.— EXPANSION  AND  CONTRACTION  IN  ROCK'S. 

i.  Col.  Totten's  Experiments  [R.  13  (vol.  xxii,  1833, 
p.  136),  46  (vol.  ii)].  a.  Ratio  of  expansion  in:  (1)  fine- 
grained granyte,  (2)  granular  limestone,  (3)  red  sandstone  = 
1 :  1.78:  1.99,  respectively,  b.  Amount  of  expansion  in  1  in. 
cubes:  (1)  .000004825  ;  (2)  .000005668;  (3)  .000009532.  c. 
Lyell  calculates  that  50  miles  in  thickness  of  crust,  with  increase 
of  6oo°  F.  to  8oo°  F.,  would  cause  elevation  of  1000  ft.  to 
1500  ft. 

2.  Bischof  s  Experiments,  a.  In  passing  from  glassy 
condition  to  crystalline,  rocks  shrink  in  volume:  (1)  Basalt, 


26 


GENERAL  GEOLOGY. 


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S  UB TERRANEAN  A  GENCIES.  2  7 

0702;  (2)  Trachyte,  .0786;  (2)  Granyte,  .1580.  b.  From 
fluid  state  to  crystalline,  shrinkage  in:  (1)  Basalt,  .1040;  (2) 
Trachyte,  .1813;  (3)  Granyte,  .2519.  c.  Results  somewhat 
remarkable  and  not  all  confirmed  [D.  Forbes,  R.  45  (xviii,  p. 
191)]. 

3.  Experiments  of  Delesse  and  Deville  [R.  53  (II, 
iv,  pp.  1312,  1380)].  a.  From  fluid  to  solid,  contract:  (1) 
Granyte,  Quartz-porphyry,  etc.,  .09  to  .11;  (2)  Syenyte,  .08  to 
•°9j  (3)  Porphyrine  forms,  .08  to  .10;  (4)  Greenstones,  .06  to 
.08;  (5)  Melaphyr,  .05  to  .07  ;  (6)  Trappean  rocks,  .03  to  .05  ; 
(7)  Volcanic  rocks,  .00  to  .04.  b.  Conclusions  of  M.  Delesse 
for  Igneous  rocks. 

( 1 )  From  crystalline  to  glassy  state,  rocks  increase  in  volume  (decrease  in 
density*)  more  rapidly  in  proportion  to  quantity  of SiOa  and  alkali  (Acidic 
Series). 

(2)  Rocks  increase  in  volume  less  rapidly  in  proportion  to  amount  of  iron, 
CaO  and  A120 >3  (Basic  Series). 

(3)  Igneous  rocks  most  deeply  seated  (ancient)  generally  of  first  group 
(acidic)  ;   those  near  surface  (modern)  commonly  of  second  group  {basic). 

(4)  Order  of  increase  of  volume  almost  exactly  the  inverse  of  order  of  fu- 
sibility. 

4.  Production  of  Columnar  Structure  in  Rocks. 

C— VOLCANOES  AND  VOLCANIC  PHENOMENA. 

i.  Form  and  Structure  of  Volcanoes,  a.  More  or 
less  conical,  built  up  of  material  ejected  from  below  through 
one  or  more  shafts  communicating  with  highly-heated  portion 
of  earth's  crust,  b.  Truncated  above,  with  basin-shaped  pit, 
or  crater,  surrounding  orifice  of  shaft,  c.  Much  variety  in 
shape  and  structure,  d.  Structure  commonly  complicated  by 
irregular  alternations  of  lava,  ash  and  cinders,  e.  Height  even 
14,500  ft.;  breadth  of  crater  variable,  even  3  miles;  depth  of 
crater  as  great  as  1000  ft. 

2.  Kinds  of  Volcanic  Cones.  A.  Eruptive.  Most 
common ;  formed  by  successive  ejections  of  molten  or  other 
material.  I.  Lava-cones,  a.  Slope  at  low  angles  (6°  to  8°) ; 
Ex. :  ^Etna,  cones  of  Hawaii  (Sandwich  Is.)  b.  Crater  in 
form  of  pit,  with  nearly  vertical  walls;  lavas  often  stratified. 
II.  Tufa-coties.  a.  Wet  cinders  or  flowing  mud.  b.  Slope 
1 50  to  300.  c.  Inward  slope  of  walls  of  crater  towards  cen- 
tral shaft,  making  bowl-shaped  depression.     III.   Cinder-cones. 

a.  Slope  of  400  or  less.  b.  Crater  restricted,  with  narrow 
rim.  IV.  Mixed  cones,  a.  Slope  from  8°  to  350,  dependent 
upon  proportions  and  alternations  of  lava,  tufa  and  cinder. 

b.  Crater  liable  to  simulate  that  of  cinder-cotie.     B.  Elevated. 


28  GENERAL  GEOLOGY. 

Caused  by  swelling  and  bursting  of  earth's  crust;    probably 
form  part  of  some  cones. 

3.  Present  Distribution,  a.  Almost  wholly  limited  to 
oceanic  islands  or  to  borders  of  continents  near  the  sea.  b. 
Nearly  all  oceanic  islands  are  volcanic,  c.  Two-thirds  of  all 
volcanoes  are  on  oceanic  islands,  d.  Mainly  confined  to  bor- 
ders of  Pacific  Ocean  and  equatorial  seas.  e.  Arranged  in 
groups  or  linear  series  [R.  1  (p.  703)].  f.  Pacific  Ocean  al- 
most completely  encircled  by  main  belt.  g.  Note  of  much  im- 
portance :  Active  volcanoes  most  common  in  geologically 
modern  strata,  h.  Number  of  existing  volcanoes,  1200  or 
more;  goo  in  archipelago  about  Borneo,  i.  Extinct  volcanoes 
very  numerous,  even  in  regions  away  from  present  coast. 

4.  Products.  A.  Liquid,  a.  Liquidity  dependent  upon  : 
(1)  amount  of  heat ;  (2)  conditions  of  fusion  (aqueous  or  aqueo- 
igneous);  (3)  nature  of  material,  b.  Special  forms  of  lava 
produced  by  cooling,  as:  (1)  Pele's  hair;  (2)  pumice;  (3)  ob- 
sidian (volcanic  glass);  (4)  vesicular  lava;  (5)  volcanic  sand. 
c.  Igneous  fusion  occurs  with  great  heat  (25000  or  more)  and 
limited  amount  of  water,  d.  Aqueo-igjieous  fusion  requires 
abundant  supply  of  water  but  not  greatest  heat  (only  8oo°). 
e.  Fcldspathic  (acidic)  lavas  less  fusible  than  augitic  (basic). 
B.  Solid.  I.  Volcanic  ash,  forming  tuffs.  II.  Cinders.  III. 
Fragmentary  masses,  a.  From  walls  of  chimneys,  b.  Ce- 
mented into  breccias,  agglomerate,  or  conglomerate.  C.  Gas- 
eous. I.  Steam,  a.  Escapes  with  ash  and  cinders  in  explo- 
sive eruptions,  b.  Not  abundant  in  lava  ejections,  c.  Largely 
from  surface  waters.  II.  Carbonic  Acid.  a.  Rather  secondary. 
b.  From  limestone,  and  possibly  other  sources.  III.  Chlor- 
hydric  Acid.  a.  From  sea- water,  mainly,  b.  Converts  oxides 
to  chlorides.  IV.  Sulphurous  Vapors,  a.  Sulphur  deposited 
secondarily,  b.  S02  vapor  not  rare ;  produces  sulphates  event- 
ually,    c.  H2S  rather  common.     V.  Nitrogen.     VI.  Hydrogen. 

5.  Association  of  Basic  and  Acidic  Lavas,  a.  Old 
opinion  of  relative  age ;  basic  group  newer,  b.  Richthofen's 
views  as  to  order  of  succession  in  Rocky  Mountain  region  :  (1) 
Propylyte,  (2)  Afidesyte,  (3)  Trachyte,  (4)  Rhyolyte,  (5)  Basalt 
[R.  54,  55  (pp.  186,  187)].  c.  Bunsen's  double  or  triple  sets 
of  "volcanic  foci."  d.  Durocher's  double  "magmas."  e. 
Lyell's  counter-statement  regarding  trachytic  lavas  overlying 
dolerytic  in  Madeira  [R.  46,  (vol.  ii,  p.  52)].  f.  Association 
well  marked  in  ancient  (Trappean)  as  well  as  modern  (Vol- 
canic) accumulations,     g.  Relations  of  both  basic  and  acidic 


S  UB  TERRANEAN  A  GENCIES.  2 9 

lavas  to  sedimentary  beds,  suggesting  possible  cause  of  associa- 
tion of  former. 

6.  Phenomena  Accompanying  Eruption.  A.  Lava 
Flows.  I.  Ebullition,  a.  Jets  of  thirty  ft.  in  most  liquid 
lavas,  b.  In  viscid  lavas  resistance  much  greater,  and  burst- 
ing of  bubbles  sometimes  throws  material  very  high  (10,000  ft., 
Vesuvius,  1779,  Sir  Wm.  Hamilton),  c.  Circulation  from 
centre  towards  sides  of  crater.  II.  Hydrostatic  Pressure,  a. 
Increases  8^  atmospheres  for  every  100  ft.  in  depth,  b.  Heat 
causes  vaporizable  substances  to  ascend,  inflating  mass  in  con- 
duit, making  general  rise  in  craters,  c.  Produces  fractures  in 
sides  of  cones.  III.  Outflow,  a.  Sometimes  over  brim  of 
crater,  but  usually  through  coincident  fractures,  b.  Common- 
ly quiet,  unless  affected  by  vapors,  c.  Superficial  extent  de- 
pendent on  liquidity  of  lava  and  topography  of  region ;  often 
many  sq.  mi.  in  area,  from  100  ft.  to  600  ft.  in  depth  [R.  1  (p. 
712),  46  (vol.  ii,  p.  52)].  d.  Scoriaceous  crust  formed  at  sur- 
face long  (even  10  years)  before  solidification  of  subjacent 
mass.  e.  Production  of  dikes,  mounds,  clinkers,  etc.  B.  Solid 
Ejections,  a.  Huge  fragments  thrown  out  in  explosive  erup- 
tions, often  to  great  distances  (from  Cotopaxi,  one  mass  of  211 
tons,  9  miles),  b.  Earthquakes  ordinarily  occur  at  same  time. 
C.  Vapor  Emissions,  a.  Ordinarily  associated  with  explo- 
sive eruptions,  b.  Important  effects  on  weather,  causing  rains, 
etc.  c.  Scrope  [R.  58]  considers  mobility  of  lavas  due  to  im- 
pregnating steam. 

7.  Process  of  Cone-formation,     a.  Successive  steps: 

(1)  Opening  of  vent;  (2)  growth  of  primary  cone  by  accumulation  of 
ejectamenta;    (3)   bursting-out  of  side-vents  ;    (4)  production  of  dikes; 

(5)  building-up  of  secondary  cones  ("parasitic  cones  "  or  "monticules  ")  ; 

(6)  formation  of  central  crater  by  bursting  or  melting  off  of  top  of  main 
cone;  (7)  rebuilding  of  cones  over  central  area  ("cone-within-cone " 
structure). 

b.  LeConte's  simile  of  exogenous  wood  [R.  3,  p.  89].  c. 
Remarks  on  great  age  of  certain  volcanoes. 

8.  Periodicity  of  Eruptions,  a.  Active,  dormant,  ex- 
tinct volcanoes,  b.  Intervals  sometimes  rather  irregular,  but 
commonly  not  so. 

9.  Explanation  of  Volcanic  Action.  A.  Require- 
ments, a.  Necessary  to  account  for :  (1)  force  of  ejection  and 
(2)  heat  of  fusion. 

(1)  Amount  of  force  required  to  raise  lavas  (Gr.  2.5-3.)  to  bottom  of 
crater  =  wt.  of  column  in  conduit=  156.25  lbs.  to  187.5  ^Ds*  Per  cu-  ft-  = 
I  atmosphere  for  each  vertical  12  ft.  (12ft.  10  in.  to  loft.  8  in. )  of  column. 
This,  in  Vesuvius  (3900  ft.  above  sea)  =  325  at. ;  in  ^Etna  (11,000  ft.), 


3o  GENERAL  GEOLOGY. 

I083  at. ;  in  Mount  Loa  (craters  10,000  ft.  to  13,000  ft. ),  833  at.  to  1083  at.; 
Cotopaxi  (20,000  ft.),  1666  at.  (2)  Quiet  eruptions  demand  exercise  of 
maximum  force  and  maximum  heat,  while  explosive  eruptions  may  occur 
under  minimum  of  force  and  heat,  owing  to  presence  of  superheated  water. 

B.  Theories.  I.  Eruption,  a.  Generally  agreed  that  ejec- 
tion is  mainly  due  to  imprisoned  vapors,  chiefly  steam.  II. 
Fusion,  a.  Source  of  heat  somewhat  in  dispute ;  several  theo- 
ries, as  below : 

(1)  Internal  Fluidity.  Supposes  existence  of  molten  interior,  throb- 
bing in  response  to  crust  movements  which  permit  access  of  surface 
waters  through  new  fissures.      \_Relic  of  early  geology]. 

(2)  Gaseous  Evolution  (subterranean).  Superheated  gases  in  interior 
of  earth  expanding  near  surface,  melting  rocks  and  forcing  them  out- 
wards ;  appeals  to  sun  for  support.  \_Kev.  O.  Fisher,  1868  [R.  44  (Nov.), 
67],  1875  [R.  61  (vol.  xii)];  N.  S.  Shaler,  1868  [R.  44  (Nov.),  67]. 

(3)  Rise  of  Heat  through  Crust,  locally  transforming  subjacent  sedi- 
ments, by  aqueo-igneus  fusion,  into  material  sufficiently  elastic  to  produce 
volcanic  phenomena.     [Sir  jfohn  Herschel,  [R.  66,  (vol.  xi,  p.  548)]. 

(4)  Aqueo-Igneous  Belt.  Thought  to  be  result  of  action  given  in  (3), 
producing  continuous  belt  of  fused  material  between  central  mass  and 
outer  crust.     [Compromise  bet-ween  (1)  and  (2)]. 

(5)  Oxidation  of  Inferior  Mass,  above  "limit  of  volcanic  water,"1  de- 
veloping heat  enough  for  effects  observed  in  volcanoes.  Sir  Humphrey 
Davy  suggested  particular  form  of  oxidation  (see  p.  24).  \_Few  hold  this, 
perhaps,  as  chief  source  of  heaf\. 

(6)  Contraction  of  Interior  more  rapidly  than  the  crust,  causing  suffi- 
cient horizontal  pressure  in  latter  to  produce  local  volcanic  action.  [ Mal- 
let's view  [R.  39,  1872]  now  accepted  by  many  of  best  authorities], 

C.  Discussion.  I.  Theory  of  Internal  Fluidity,  a.  Based 
upon  hypothesis  now  but  little  supported,  b.  Limits  thickness 
of"  crust  more  than  seems  warranted  by  results  of  recent  phys- 
ical research,  c.  Effects  too  local  for  support  of  this  theory, 
in  toto.  d.  "Limit  of  volcanic  waters"  probably  far  above 
isogeotherm  of  8oo°  F.  (temp,  of  aqueo-igneous  fusion);  hence, 
surface  waters  could  not  penetrate  to  igneous  interior,  e.  Ad- 
vocates adopt  modifications  ("local  thinnings,"  and  "honey- 
combed remains"  within  crust  separated  from  interior  mass), 
which  practically  revoke  theory  as  regards  volcanoes.  II.  Sub- 
terranean Gases,  a.  Sun  generally  considered  as  now  in  con 
dition  of  earth  at  an  earlier  stage ;  from  former  vapors  abun- 
dantly emitted,  b.  Volcanic  activity  formerly  greater  on  the 
earth,  c.  Lavas  usually  charged  with  vapors,  d.  Action  of 
this  kind  may  take  place  far  below  limit  of  volcanic  waters. 
e.  This  view  may  be  held  as  accessory  to  theory  (6),  though 
Fisher  opposes  latter.     III.  Ascent  of  heat.     a.  Deposition  of 

1  Phraseology  suggested  by  Le  Conte  [R.  3  (p.  92)]  to  indicate  point  where  action  of 
jravity  on  surface  waters  balances  reverse  action  of  interior  heat. 


S  UB  TERRANEAN  A  GENCIES.  3 1 

sediments  causes  gradual  upward  movement  of  isogeotherms, 
possibly  sufficient  to  account  for  certain  volcanic  phenomena, 
as  mud-throws  and  some  explosive  ejections,  b.  Increase  of 
temp,  too  slight  and  too  slow  for  igneous  fusion,  c.  Receives 
some  apparent  support  from  occurrence  of  active  volcanoes 
mainly  in  recent  strata.  IV.  Zone  of  Aqueo-igneous  Fusion,  a. 
Open  to  objections  under  I  and  III.  V.  Chemical  Theory,  a. 
Probably  explains  certain  phenomena  and  rightly  accounts  for 
part  of  heat.  b.  Sir  Humphrey  Davy's  special  modification 
almost  purely  hypothetical,  c.  Oxidation  not  only  chemical 
source  of  heat. 

Much  heat  is  disengaged  in  formation  of  chlorides.  bro77iides,  iodides  and 
snip/tides,  and,  contrary  to  general  rule,  heat  is  also  given  off  in  decomposi- 
tion of  nitrous  oxide  and  hydrogen  peroxide  [R.  59]. 

VI.  Mechanical  Theory,  a.  Explains  not  only  volcanoes 
but  also  other  kinds  of  igneous,  as  well  as  sub-igneous,  action.1 
b.  Accords  well  with  commonly  accepted  theories  of  earth's 
general  history. 

Earth,  in  cooling,  first  formed  thin,  solid  crust,  acting  as  non-conduct- 
ing envelope  to  fluid  mass  within.  Interior  magma,  in  cooling,  contracted 
and  still  contracts  more  rapidly  than  crust,  because  coefficient  of  contraction 
is  greater  at  high  temperature  and  because  temperature  of  crust  has  be- 
come nearly  stationary.  Result  must  be  horizontal  pressure  from  yielding 
of  crust  to  adjust  itself. 

c.  Two  prominent  modifications  of  theory:  (1)  arching  of 
strata  by  the  pressure,  allowing  portions  of  interior  mass  to 
escape;  (2)  more  common  view  of  crushing  of  material  and 
final  mechanical  fusion  of  subjacent  portion. 

D.— IGNEOUS  ACTION  NOT  VOLCANIC. 

i.  Nature  of  Trappean  Ejections,  a.  Distribution 
same  as  volcanoes,  but  also  common  in  regions  of  extinct  vol- 
canoes, b.  Produced  by  eruption  through  fissures,  c.  Mate- 
rial similar  to  volcanic  masses,  but  more  compressed. 

2.  Interbedded,  or  Contemporaneous  Traps,  a. 
Characterized  by:  (1)  position  among  stratified  beds,  conform- 
able with  overlying  sediments;  (2)  unaltered  condition  of  su- 
perimposed layers ;  (3)  occurrence  of  tuffs,  etc. ;  (4)  slaggy, 
or  scoriaceous,  character  at  top  and  bottom  of  lava  sheets,  b. 
Material  both  crystalline  and  fragmental,  former  somewhat  re- 
stricted, latter  of  all  varieties. 

Dioryte,  hyperyte,  quarts-porphyry,  etc.,  not  known  as  interbedded  trap, 
though  meldphyr  and  felsyte  are  not  uncommon,  also  some  rocks  of  Vol- 
canic Division. 

1  This  theory  will  be  more  fully  examined  under  head  of  Mountain  Elevation  (p.  38). 
See  also  remarks  under  Slaty  Cleavage  beyond  (p.  37). 


32  GENERAL  GEOLOGY. 

c.  Structure  and  texture  of  sheets  similar  to  modern  lava 
flows  from  volcanoes,  with  induced  modifications  resulting  from 
age  and  pressure,  d.  Sheets  occur  in  series  alternating  with 
sedimentary  beds.  e.  Tuffs  of  given  series  commonly  resem- 
ble lavas  of  same  group,  f.  Sedimentary  masses  enclosed  in 
tuff.  g.  Illustrations  from  contemporaneous  traps  of  "  the  great 
Northwest  lava-flood"  extending  from  Big  Horn  Mts.  to  Pacific 
Ocean  (area  nearly  175,000  sq.  mi.)  h.  Some  European 
fissure-eruptions 

3.  Intrusive,  or  Subsequent  Traps  (see  Igneous 
Dikes,  p.  21).  a.  Material  filling  fissures  in  rocks  previously 
arranged,  b.  Occur  in  dikes,  offsets,  bosses,  sheets  and  necks, 
always  following  lines  of  least  resistance,  c.  Sometimes,  in 
sheets  and  offsets,  may  appear  contemporaneous,  locally,  d. 
Crystalline,  of  all  Trappean  varieties ;  fragmental  varieties 
normally  wanting,  represented,  however,  by  agglomerate  necks. 
e.  Dikes  rarely  formed  of  diotyte  or  members  of  Feldspathic 
Family,     f.  Examples  of  intrusive  traps : 

(1)  Amorphous  Masses  more  or  less  abundant  in  Scotland,  Wales  and 
elsewhere:  (2)  dikes  well  represented  in  U.  S.  by  trap  ridges  of  Conn. 
Valley,  Mt.  Tom  and  Holyoke  Mts.,  N.  J.  Highlands  and  Lake  Superior 
bluffs  ;  elsewhere  common,  as  Giant's  Causeway  and  Fingal's  Cave  j  (3) 
sheets,  necks  and  offsets,  more  local. 

4.  Igneous  Granytes.  a.  Subject  of  much  discussion ; 
formerly  considered  fundamental  or  part  of  original  crust,  b. 
All  granyte  regarded  as  igneous  until  recently;  greater  portion 
now  considered  metamorphic.  c.  Position  and  relations  to 
other  rocks  indicate  cooling  at  great  depths  under  pressure. 
d.  Growing  opinion  that  Granytic  rocks  are  rarely  or  never  true 
igneous  deposits,  e.  Abundant  proof  of  Aqueo-igneous  origin. 
For  arguments  on  both  sides,  see  Hunt  [R.  13,  (New  Series, 
vol.  i,  pp.  82,  182),  56  (pp.  s,  ss,  43,  65,  183,  189-191)]; 
Scrope  [R.  65  (vol.  xii,  p.  326)];  Scheever  and  others  [R.  53 
(II),  vol.  iv,  pp.  468,  1018,  131 2  ;  vi,  644  ;  vii.  275  ;  vii,  500] ; 
Sorby  [R.  62  (February,  1858)];  Rose  [R.  62  (xix,  p.  32)]; 
Delesse  [R.  63  (vol.  vii,  p.  190)];  Jukes  and  Geikie  [R.  2 
(chap,  xii)];  Le  Conte  [R.  3  (p.  217)].  f.  Notes  of  personal 
observations  on  granytes  of  Rocky  Mts.  and  region  in  Brit. 
Amer.  N.  W.  of  Lake  Superior. 

E.—SECONDAR  Y  IGNEOUS  ACTION. 

I.  Geysers,  a.  Intermittent  explosive  thermal  springs. 
b.  Occur  in  Iceland,  New  Zealand  and  Yellowstone  Park, 
U.  S.,  associated  with  ancient  volcanic  outflows,      c.  Great 


S  UB TERRANEAN  A  GENCIES.  33 

Geyser,  Iceland:  Bunsen  [R.  86  (lxxii,  1847,  pp.  159-170)]; 
Bischof  [R.  72,  p.  225  (quoted  in  R.  73,  187 1,  p.  129)].  d. 
New  Zealand  geysers  [R.  71,  p.  432  (quoted  in  R.  73,  187 1, 
p.  128)].  e.1  Yellowstone  (rather,  Madison,)  geysers;  some 
account  of  explorations;  (1)  Lieut.  G.  C.  Doane  [Rep't  upon 
Yellowstone  Expedition  of '1870  (Sen.  Ex.  Doc,  51,  4.1st  Cong., 
3d  Sess.)\ ;  (2)  Capts.  Barlow  and  Heap  [Reconnaissance  of 
Sources  of  Yellowstone  River,  187 1  [Sen.  Ex.  Doc,  66,  42^ 
Cong.,  2d  Sess.)] ;  (3)  Hayden,  Peale,  etc.  [R.  73,  1871,  1872, 
1877,  1878];  (4)  Jones,  Heizmann,  Comstock,  1873  [R.  55]; 
(5)  Ludlow,  Grinnell,  E.  S.  Dana,  1875  [Carroll,  Montana,  to 
Yellowstone  Park  (War  Dep't)].  f.  Personal  observations; 
descriptions  of  leading  geysers,  as  White  Dome,  Clepsydra, 
Fountain,  Impulsive,  etc.,  of  Lower  Fire  Hole — Old  Faithful, 
Castle,  Giant,  Giantess,  Bee-hive,  Grotto,  Grand  and  Fan  gey- 
sers of  Upper  Basin — with  remarks  on  phenomena  and  de- 
posits JR.  55  (pp.  241-259),  74,  76,  78  (1875,  B,  p.  97)].  g. 
Periodicity  of  geysers,  h.  "Sympathy"  between  separated 
geysers  [R.  74]. 

2.  Theory  of  the  Geyser  [R.  3  (p.  99)].  I.  Origin. 
a.  Relation  to  volcanic  activity,  b.  Produced  by  infiltration, 
through  fissures,  of  meteoric  water,  c.  Only  formed  by  sili- 
ceous waters,  d.  Waters  always  contain  alkaline  carbonates. 
e.  Bunsen's  theory  of  formation  of  tube  and  chimney.  II. 
Eruption,  a.  Mackenzie's  theory  of  subterranean  caverns, 
adopted  by  Bischof  [R.  72,  73  (1871,  p.  129)]  for  New  Zeal- 
and, and  applied  by  the  author  to  certain  geysers  of  Yellow- 
stone Park  [R.  55,  p.  225  et  sea.],  b.  Bunsen's  theory  of 
eruption  (unequal  heating  at  different  depths)  sufficient  to  ex- 
plain prominent  facts  and  capable  of  experimental  verification. 

3.  Thermal  Springs  in  Volcanic  Districts.2  a. 
Non-eruptive  or  sometimes  eruptive,  b.  Antecedents  or  con- 
sequents of  geysers;  often  siliceous,  c.  Deposits  [see  M9  1. 
Geysers,  e.]:  (1)  siliceous,  in  form  of  chimneys  of  opal  or 
quartz  (rarely);  (2)  calcareous  cones  and  basins  of  travertine 
along  bottoms  of  streams,  even  forming  limestones  of  considera- 
ble local  extent  (Gardiner's  River,  Yellowstone  Park);  (3)  sul- 
phurous, as  sulphur  incrustations,  and  (4)  resulting  products, 
such   as   alum,  gypsum,   etc.      d.    Solfataras;    commonly   in 

1  All  references  under  e  may  be  found  in  the  Cornell  University  Library. 

2  Certain  classes  of  springs  in  which  the  action  of  heat  is  commonly  coincident  if  not 
essential,  might  properly  be  discussed  here,  but  it  is  thought  best  to  consider  them  under 
the  head  of  Stibterrancan  Water  beyond  (p.  41). 


34  GENERAL  GEOLOGY. 

Trachytic  rocks,  e.  Salses  and  mud-volcanoes,  f.  Fumar- 
oles.  g.  Carbonated  springs,  h.  Personal  observations  at 
other  points  in  Yellowstone  Park. 

Ref. : — i  (pp.  697-723),  2  (chaps,  xvi,  xix,  and 
xx  to  p.  358),  3  (pp.  76-104),  4-6,  8-12,  27, 
41,  46,  47,  49,  55,  56,  58,  60,  71,  72,  73 
(1871,  1872,  1877,  1878),  74,  76,  79,  82,  84. 

DIVISION  B.— MOVEMENTS  IN   EARTH'S 
CBTJST. 

A.— EARTH Q UAKE  PHENOMENA. 

i.  Character  and  Distribution,  a.  Mallet's  definition 
[R.  88  (1847,  Part  2,  p.  30;    1850,  pp.  1-87;    1851,  pp.  272- 

32°)]- 

Earthquake  consists  of  "waves  of  elastic  compression,  from  vertical  to 
horizontal,  in  any  azimuth,  through  crust  of  earth,  from  any  centre  of 
impulse,  or  more  than  one,  and  which  may  be  attended  with  sound- 
waves and  sea-waves,  depending  on  impulse  and  circumstances  of  posi- 
tion." 

b.  Average  recorded  number  575  per  annum,  but  greater 
number  not  catalogued  ;  earth  probably  never  wholly  free  from 
quakings.  c.  Most  common  in  volcanic  districts  [see  R.  79 
(PI.  X)  or  any  good  Physical  maps,  as  in  R.  4,  etc.] 

2.  Relation  to  Volcanic  Action,  a.  Eruptions  rarely 
occur  without  earthquakes,  before  and  during  ejection,  b. 
Especially  characteristic  of  explosive  eruptions.  c.  Earth- 
quakes not  unfrequently  cease  upon  eruption  of  neighboring 
volcanoes,  and  vice  versa. 

3.  Cosmical  Relations.  a.  Earthquakes  occur  more 
commonly  in  winter  than  in  summer;  difference  trifling,  b. 
C.  More  liable  to  occur  under  diminished  atmospheric  pressure. 
Alexis  Perrey's  laws  of  lunar  action  : 

(1)  Earthquakes  most  frequent  with  moon  on  meridian  (flood-tide). 
(2)  At  syzygies  (new  and  full  moon,  high  flood-tide)  a  little  more  fre- 
quent than  at  quadratures  (half-moon).  (3)  Somewhat  more  frequent  in 
perigee  (moon  nearest  earth,  highest  flood-tide)  than  in  apogee  (moon 
farthest  from  earth). 

4.  Phenomena  and  Effects,  a.  Sudden  movements 
(undulatory)  in  earth's  crust,  producing  temporary  and  perma- 
nent displacements;  alteration  of  drainage.  b.  Vorticose 
movements,  c.  Production  of  fissures,  d.  Inundations,  e. 
Shocks  in  mines,  f.  Destruction  of  life  and  property,  g. 
Storms,     h.  Earthquake-"  bridges."     i.  Peculiar  sounds. 


^  UB TERRANEAN  A  GENCIES.  3 5 

5.  Seismographs  and  Seismometers  [R.  3,  p.  122]. 
a.  Palmieri's  telegraphic  seismograph  [R.  60,  p.  141].  b. 
Cavalleri's  pendulum  seismometer  [R.  62,  xix,  1866,  pp.  102— 
116].  c.  Simple  forms  sometimes  employed,  as  basin  of  mo- 
iasses,  etc. 

6.  Mallet's    Laws    of  Earthquake  Motion  [R.  85]. 

I.  "Earth-wave  of  shock'''  is  result  of  sudden  impulse,  a. 
May  be:  (1)  volcanic  eruption;  (2)  cracking  of  rock  under 
tension;  (3)  generation  of  steam  from  spheroidal  state  of 
water;  (4)  condensation  of  steam.  II.  Transmitted  with 
great  velocity,  affecting  a?iy  spot  but  momentarily.  a.  Veloc- 
ity dependent  upon  nature  of  rock,  etc.  b.  Mallet's  exper- 
iments [R.  3,  p.  ni[  with  artificial  earthquakes,  c.  Mallet's 
observations  (1857)  on  Calabrian  earthquakes;  mean  velocity 
of  789  ft.  per  second  (658  ft.  to  989  ft.,  extremes).  III. 
Waves  travel  in  spheroidal  shells,  spreading  in  irregular  closed 

curves  ("  coseismal  lines  "),  widening  in  proportion  to  distance 
from  central  impulse,  a.  "Coseismal  lines"  modified  by:  (1) 
form  and  dimensions  of  central  impulse;  (2)  variations  in 
hardness,  density,  texture  and  structure  of  rocks ;  (3)  sudden 
changes  in  rocks,  producing  return  waves.  IV.  "Angle  of 
emergence  =  900  (seismic  vertical)  over  central  impulse,  decreas- 
ing with  distance  from  seismic  vertical,  a.  Destructive  effects 
commonly  decrease  inversely  as  "angle  of  emergence";  be- 
cause overthrowing  power  increases  as  angle  decreases.  V. 
"  Velocity  of  shock"  not  rapid,  but  "transit  of  wave"  about  half 
as  rapid  as  cannon-ball.  a.  "Velocity  of  shock"  only  10  ft. 
to  15  ft.  per  second,  b.  "Amplitude"  of  wave  usually  but  a 
few  inches. 

7.  Explanation  and  Discussion.  I.  Explosive  earth- 
quakes, a.  Velocity  of  shock  very  great,  owing  to  very  sud- 
den and  strong  impulse,  b.  Position  of  central  impulse  (focus) 
not  very  deep,  otherwise  height  of  wave  and  velocity  of  shock 
would  be  too  much  diminished  to  produce  such  violent  effects. 

II.  Vorticose  earthquakes,  a.  Less  common  than  often  sup- 
posed ;  vorticose  movements  frequently  produced  by  ordinary 
vibrations,  b.  Mainly  due  to  concurrence  and  interference  of 
waves,  produced  by : 

(1)  Unequal  velocity  of  different  waves  (probably  not  a  common  cause 
in  earthquakes) ;  (2)  reflection  of  waves  in  passing  through  media  of 
varying  density. 

III.  Spreading  earthquakes,  a.  Coseismal  lines  will  be :  (1) 
Circular,  when  waves  pass  through  material  of  uniform  elas- 
ticity ;  (2)  elliptical,  when  elasticity  of  rock  differs  considerably 


36  GENERAL  GEOLOGY. 

in  directions  mutually  transverse ;  (3)  linear,  when  structure  is 
such  as  to  produce  effect  of  non-elastic  material  in  two  opposite 
directions.  This  last  result  is  most  frequently  due  to  wave-re- 
flection in  passing  through  strata  of  varying  density ;  hence 
linear  earthquakes  are  most  common  along  mountain  axes. 
IV.  Sea-wave.  a.  Velocity  due  to  size  of  wave;  much  less 
than  earth-wave,  though  often  from  300  mi.  to  nearly  500  mi. 
per  hour.  b.  Distance  traversed  very  much  greater  than 
earth-wave,  because : 

(1)  Earth-waves,  being  spherical,  diminish  in  oscillation  as  square  of 
distance,  while  water-waves  (circular)  diminish  only  in  proportion  to  dis- 
tance. (2)  Earth-waves  traverse  heterogeneous  medium,  causing  abnor- 
mal reduction  in  oscillation,  by  reflection  and  refraction,  and  loss  of  effect 
from  fractures  and  transformation  of  energy. 

c.  Reduction  in  velocity  due  to  decrease  in  depth  of  water; 
measurement  of  depth. 

Great  size  of  sea-wave  causes  it  to  "drag  bottom"  in  comparatively  deep 
water.  Principle  is  established  that  every  wave  traverses  its  own  length 
during  time  of  one  oscillation.  Length  of  wave  thus  ascertained  from  ob- 
served velocity  and  time  of  oscillation,  depth  of  sea  is  calculated  from  dif- 
ference between  free  velocity  and  actual  retarded  velocity  [A.  D.  Bache,  R. 
83,  1862,  p.  238]. 

B.-SECULAR  MOVEMENTS. 

i.  Relation  to  Sea-Level,  a.  Changes  of  level  in  land 
must  ordinarily  affect  water-level,  hence  : 

(1)  Actual  amount  of  any  movement  of  elevation  is  less  than  apparent 
by  just  the  amount  of  coincident  depression  of  sea-level.  (2)  Depression 
of  land  is  greater  than  apparent  by  an  amount  equal  to  coincident  elevation 
of  sea-level.  But  (3)  actual  additions  to  land  surface  being  (apparently) 
inappreciable,  sea-level  may  be  regarded,  for  convenience,  as  a  fixed  plane. 
b.  Cosmical  causes  may  change  level  of  sea  alone,  but 
these  effects  are  commonly  compensated  [Croll,  R.  62  (April, 
1866;  June,  1867;   1868,  p.  382)]. 

2.  Proofs  of  Elevation  of  Land  [Lyell,  R.  46,  89].  a. 
Raised  rocks,  reefs,  old  sea-beaches,  etc. : 

Examples  :  (1)  Scandinavian  Peninsula,  N.  of  Stockholm  (and  part  of 
Russia),  '■'raised  beaches"  50  to  70  miles  inland,  at  height  of  100  to  700 
ft.,  with  barnacles  and  shells  attached;  (2)  South  America,  Chili  and 
southward,  beaches,  1180  miles  on  E.  coast,  and  2075  miles  on  west,  100 
ft.  to  3000  ft. ;  (3)  Siberian  Coast  for  600  miles  ;  (4)  Mediterratiean  Sea- 
coast  in  places  (Bay  of  Naples,  20  ft.),  Temple  of  Jupiter  Serapis. 

b.  Old  caves  formed  at  sea-level,  now  8  ft.  to  100  ft.  above, 
as  along  coasts  of  Scotland,  c.  Terraces  along  sea-border. 
d.  Human  works,  as  piers,  etc.,  and  Swedish  commission 
guages. 

3.  Evidences  of  Depression,     a.  Submerged  forests. 


S  UB  TERRANEAN  A  GENCIES.  3  7 

b.  Growth  of  coral  islands,     c.  Fjords.1     d.  River  deltas,     e. 
Encroachment  of  sea  on  land  over  wide  areas. 

Examples:  (i)  Southern  Sweden,  gradual  approach  of  streets  to  sea- 
level,  stone  set  by  Linnseus  in  1749,  100  ft.  nearer  sea  in  1S36.  (2)  IV. 
Coast  of  Greenland  for  600  miles,  submerging  huts  and  boat-poles. 

4.  Theoretical  Considerations,  a.  Areas  of  subsid- 
ence commonly  in  regions  of  great  accumulation  of  sediments. 
b.  Consequent  rise  of  isogeotherms,  basis  of: 

(1)  Babbage's  Theory  [R.  66,  vol.  II,  p.  73].  Expansion  of  crust  ver- 
tically, causing  elevation.    [Conflicts  with  fact  given  under  a]. 

(2)  HerscheTs  Theory  [R.  66,  vol.  ii,  pp.  548,  596].  Result  of  rise  of 
isogeotherm,  subsidence,  due  to  chemical  change  and  aqueo-igneous  fusion. 

c.  Commonly  accepted  opinion  that  movements  are  due  to 
contraction  of  earth  from  secular  cooling. 

Ref.  : — 1  (p.  741),  2  (chaps,  xvii,  xviii),  3  (pp. 
104-132),  4-6,  8-1 1,  27,  35,  41,  46,  47,  79, 
80,  81,  84,  85,  87. 


DIVISION  C!-LATEEAL  PRESSURE  FROM 
CONTRACTION. 

i.  Foldings,  Contortions,  etc.  a.  Plainly  due  (on 
large  scale)  to  subsidence  of  crust,  b.  Modified  by  texture 
and  structure  of  included  terranes.  c.  Fractures  least  com-- 
mon  in  contorted  strata,  d.  Slaty  cleavage  associated  with 
flexures. 

2.  Joints,  Fissures,  Faults,  a.  Mainly  due  to  eleva- 
tion of  portions  of  earth's  crust,  b.  Result  of  non-elastic 
nature  of  material,  c.  Indicate  cleavage-structure  in  crust 
transverse  to  pressure. 

3.  Slaty  Cleavage,  a.  Theory  of  Sharpe  [R.  65,  vol. 
iii,  p.  87]  deduced  from  distortion  of  fossils,  etc.  b.  Sorby's 
experiments  with  foreign  particles  in  clay  [R.  62,  2d  Ser.,  vol. 
xi,  p.  20].  c.  Tyndall's  experiments  and  conclusions  [R.  62 
(2d  Ser.,  vol.  xii,  p.  35),  92  \appendix)\  d.  Contraction  hori- 
zontally in  direction  of  pressure,  extension  vertically,  no  change 
in  direction  of  strike.  e.  Ratio  of  compression  and  exten- 
sion averages  nearly  6 :  1  (from  2:1  to  n  :  1). 

4.  Elevation  of  Mountains,     a.  Foldings,  contortions, 

1  The  proofs  of  subsidence  afforded  by  coral  reefs  and  fjords  will  be  better  appreciated 
by  the  student  later  in  the  course. 

2  The  argument  of  the  subject  of  this  DIVISION  is  given  in  the  later  text-books 
[R.  1  (p.  73s,  et  seq.),  2  (pp.  358-360),  3  (p.  252)].  See  also  J.  M.  Wilson  [R.  44,  v,  p. 
2o6j,  and  R.  in  the  text. 


38  GENERAL  GEOLOGY. 

plications  and  slaty  cleavage  always  associated  with  mountain 
chains,  b.  Strata  20,000  ft.  to  40,000  ft.  thick  in  moun- 
tainous regions ;  hence  where  slaty  cleavage  is  prominent, 
mountain  chains  now  100  mi.  broad  originally  extended  250 
mi.  horizontally,  and  elevation  of  central  portion  is  wholly  ex- 
plained by  lateral  pressure.  c.  Much  folded  and  greatly 
cleaved  mountains  result  of  subsidence ;  those  resulting  from 
crust  elevation  commonly  less  folded  and  little  cleaved,  but 
much  fractured  and  faulted,  d.  Mechanical  theory  [(6),  p.  30; 
VI,  p.  31]  of  volcanic  action,  therefore,  applies  here.  e.  Prog- 
ress of  mountain  elevation  illustrated  : 

(1)  Sinking  of  large  area  of  crust  (geosynclinal)  by  contraction  of  mass 
within,  produces  foldings,  contortions,  and  finally  slaty  cleavage ;  com- 
pression greater  in  synclinals,  hence  synclinoritim  is  more  permanent 
mountain  chain,  as  Jura  and  portions  of  Appalachian  Mts. 

(2)  Elevation  of  large  tract  (geanticlinal)  produces  tension  in  strata 
and  consequent  fissures  and  faults  of  great  extent.  This  form  (anticli- 
norium)  of  mountain  chain  therefore  less  permanent,  as  Rocky  Mts.,  etc. 

5.  Formation  of  Continents  and  Oceanic  Depres- 
sions, a.  Continents  represent  first  cooled  areas  with  sub- 
sequent additions,  b.  Oceanic  basins  later  cooled  areas  of 
greater  subsidence,  c.  General  remarks  on  growth  of  conti- 
nents. 

Ref. :— 1  (pp.  735-754),  2  (pp.  358-36o)>  3  (PP- 
240,  252,  etc.),  13  (II,  xxii,  1856),  56  [Index). 


DIVISION  D.- ALTERATIONS  OF  TEXTURE 

AND  COMPOSITION. 

1.  Metamorphism.  a.  Effects:  (1)  consolidation ;  (2) 
change  of  color;  (3)  loss  of  vaporizable  ingredients;  (4)  ob- 
literation of  fossils;  (5)  crystallization;  (6)  foliation,  b.  Caused 
by  chemical  action  induced  or  modified  by  heat,  pressure, 
moisture  and  alkalies. 

(1)  Metamorphism  in  dry  way  illustrated  by  effects  of  igneous  protru- 
sions on  adjacent  rocks ;  (2)  effect  of  pressure  shown  by  formation  of 
marble  from  calcite  without  loss  of  CO2  [Sir  James  Hall's  experiments 
(R.  42,  vol.  vi,  p.  95)];  (3)  combined  water  of  rocks  probably  sufficient 
for  changes  observed;   (4)  alkalies  assists  fusion  and  solution. 

c.  Cycles  of  metamorphism.  d.  Sorby's  study  of  "  Micro- 
scopical Structure  of  Crystals"  [R.  65,  vol.  xiv,  p.  453]. 

2.  Pseudomorphism  [R.  57  (vol.  i,  p.  53),  29  (p.  222), 
56  (Index)],     a.  Alteration  of  composition  without  change  of 


SURFACE  AGENCIES.  39 

form,  in  minerals,     b.  Due  to  transfer  of  particles  by  solutions 
(replacement),     c.  Petrifaction  essentially  same  process. 

Ref.  :— 1  (p.  724),  2  (pp.  50,  360),  3  (p.  215), 
9,  10,  29,  46,  47,  56,  87. 


SECTION  II -SURFACE  AGENCIES. 

DIVISION  A.— ACTION  OF  WATER. 

A.— THE  OCEAN  AND  INLAND  SEAS. 

i.  Erosion  of  Land.  a.  Maximum  effect  produced 
along  shore,  but  probably  more  or  less  of  sub-marine  denuda- 
tion in  shallow  water  elsewhere,  b.  Erosive  action  progress- 
ing on  all  coasts,  but  most  abundant  in  Scotland  and  Norway, 
Cape  Horn,  etc.;  more  extensive  in  high  latitudes,  c.  Steven- 
son [R.  42,  xvi,  pp.  25,  28],  found  force  of  breakers  on  coasts 
of  Scotland : 

(1)  In  summer,  611  lbs.  per  sq.  ft. ;  (2)  in  winter,  2086  lbs. ;  (3)  during 
heavy  storms  as  much  as  6000  lbs. 

d.  Effects  vary  with :  ( 1 )  height  of  tides ;  (2)  force  of  waves; 
(3)  outline  of  coast;  (4)  texture  and  structure  of  rocks;  (5)  in- 
clination of  strata;  (6)  direction  of  prevalent  winds,  e.  "Shore 
platform,"  or  line  of  no  erosion,  just  above  low  tide.  f.  Line 
of  greatest  erosion  somewhat  above  half-tide.  g.  Bays  formed 
in  yielding  strata,  headlands  left  of  tougher  rocks,  h.  Caverns, 
"blow-holes"  and  undermining  of  coast,     i.  Examples  : 

(1)  Cliffs,  headlands,  "spectral  islands,"  caverns,  bays,  etc.,  Norway, 
Brit.  Is.,  and  elsewhere;  (2)  washing  away  of  old  towns  on  English 
coast;  (3)  U.  S.  coast  from  N.  of  Boston  to  Charleston,  S.  C,  appreciably 
wasting  (9  ft.  per  annum  at  Cape  May) ;  (4)  numerous  instances  of  bays, 
coves,  cliffs,  etc.,  along  shores  of  Great  Lakes,  as  "Pictured  Rocks,"  L. 
Superior,  bluffs  of  L.  Erie,  etc. ;  (5)  shores  of  Australia,  and  peculiar 
forms  in  Bay  of  Islands,  New  Zealand  [Dana]. 

2.  Transportation,  a.  Ocean  currents  carry  masses  of 
"Gulf-weed"  and  included  life,  also  fine  mineral  particles,  b. 
Waves  move  immense  masses,  but  only  short  distances,  c. 
Bache's  statement  concerning  transportation  of  siliceous  sand 
to  S.  extremity  of  Florida,  d.  Landward  movement  of  waves 
limits  transportation  of  detritus  seaward,  e.  Density  of  sea- 
water  enables  it  to  carry  material  farther,  or  larger  particles. 

3.  Mechanical  Deposition,  a.  Probably  much  mate- 
rial is  deposited  by  oceanic  tides  and  currents  [see  Leconte  (R. 
13,  vol.  xxiii,  p.  46,  1857)].     b.  Examples: 


4o  GENERAL  GEOLOGY. 

(i)  Banks  of  Newfoundland,  formed  by  meeting  of  Gulf  Stream  with 
cold  Arctic  current;  (2)  Bahama  banks  and  other  shoals  formed  by  ma- 
terial received  from  Amazonian  current;  (3)  submarine  banks  off  coasts 
of  German  Ocean ;  (4)  pebbles  have  been  brought  up  off  Cape  of  Good 
Hope,  in  100  fathoms,  some  miles  from  land  [Jukes  and  Geikie]. 

C.  Soundings  show  large  portion  of  ocean  bed  to  be  covered 
with  non-transported  ooze.  d.  Waves  produce  detrital  islands 
along  coasts  by  pushing  up  material  of  submarine  banks. 

4.  Chemical  Deposits,  a.  Sea  contains  less  CaC03 
than  most  rivers,  hence  deposition  must  occur,  b.  Precipita- 
tion rather  local,  as  shells,  etc.,  abstract  very  considerable 
quantity,     c.  Salt  lakes, 

(1)  Formed  by  excessive  evaporation  or  by  disjunction  from  sea;  (2) 
deposits  alkaline  (from  alkaline  carbonates)  in  volcanic  regions,  or  in  re- 
gions covered  by  volcanic  waste,  as  in  Mono  Lake  and  elsewhere  in  W. 
U.  S. ;  (3)  precipitate  saline  (from  alkaline  chlorides)  in  regions  of  ordi- 
nary sediments  ;  gypsum  first  deposited,  then  common  salt,  leaving  MgCls 
as  menstruum  finally,  as  in  Dead  Sea;Gt.  Salt  Lake,  Utah,  still  deposit- 
ing NaCl ;  (5)  Dilution  of  inland  lakes  once  arms  of  the  sea,  illustrated 
by  L.  Champlain  [R.  72,  104  (G.  K.  Gilbert,  1872)]. 

'B.— CIRCULATION  OF  WATER  UPON  LAND.* 

1.  Action  of  Rain.  I.  Mechanical,  a.  Washes  off  fine 
material,  exposing  new  surfaces  to  weathering  influences,  b. 
Scores  out  gullies  in  uncompacted  strata ;  forms  earth-pillars 
beneath  protecting  stones,  c.  Adds  to  power  of  streams  by 
freshets.  II.  Chemical,  a.  Due  to  presence  of  C02,  increas- 
ing solvent  power,     b.  Assists  chiefly  in  disintegration. 

2.  Rivers,  Creeks,  etc.  I.  Character,  a.  Size  varies 
according  to:  (1)  area  of  drainage;  (2)  amount  of  precipita- 
tion ;  (3)  evaporation ;  (4)  physiography  of  hydrographic  basin  ; 
(5)  geological  structure,  b.  Pitch  depends  mainly  on  charac- 
ter of  surface  and  amount  of  water,  modified  by  geological 
structure  ;  varies  between  high  and  low  water,  c.  Velocity  is 
determined  by  pitch  and  depth.  II.  Erosion,  a.  Cascade 
portion,  b.  Torrent  area.  c.  River  portion,  d.  Flood- 
ground,  e.  Ground  plan  and  profile,  f.  Potholes,  g. 
Causes  of  variations  in  Ithaca  gorges,  h.  Striking  examples 
of  erosion : 

1)  Colorado  canons,  300  miles,  vertical  walls,  3000  ft.  to  6000  ft. ;  (2) 
Yellowstone  canons  and  others,  2000  ft.  and  more,  worn  in  volcanic  rocks ; 
(3)  Niagara  gorges,  ancient  and  modern,  7  miles,  600  ft.  to  1200  ft.  wide, 
200  ft.  to  300  ft.  deep. 

1  For  a  full  appreciation  of  the  importance  of  this  subject,  consult:  Hutton's  Theory 
of  the  Earth  [R.  42,  vol.  i,  1785,  p.  209  (also  enlarged  and  separately  issued  in  1795)]; 
\Vhitaker  [R.  44,  vol.  iv,  p.  447  (bibliography  to  1867)] ;  also  R.  46,  57,  87,  q^.  o±. 


SURFACE  AGENCIES.  4i 

III.  Transportation,  a.  Force  of  current  increases  as  sixth 
power  of  velocity,  b.  Transportive  power  increased  by  loss 
of  wt.  (|  to  |)  of  rock  in  water,     c.   Experiments  show : 

(i)  Fine  clay  is  moved  when  current  attains  velocity  of  900  ft.  per  hour  ; 
(2)Jine  sand  moves  in  water  with  velocity  of  1800  ft.  per  hour;  (3)  coarse 
sand  (size  of  linseed)  requires  velocity  of  2400  ft.  per  hr.  ;  (4)  gravel, 
3600  ft.  ;  (5)  pebbles,  1.364-  miles  per  hr. ;  (6)  angular  stones  (size  of 
hen's  egg),  2.045+  miles. 

d.  Effects  due  to  sudden  changes  in  velocity,  e.  Amount 
of  silt  carried  by  rivers  varies  greatly. 

Mississippi  carries  annually  to  Gulf  of  Mexico  406,250,000  Ions  of  sedi- 
ment =  T8Ltfff  °f  wt-  and  Woo"  °f  v°lume  °f  tne  water,  also  pushes  44.500,- 
000  tons  sea-ward.  Ganges  discharges  annually  378,100,000  tons,  brought 
from  a  basin  of  less  than  £  the  area  of  the  Mississippi.  [Humphreys  and 
Abbott.) 

Hoang  Ho  transports  yearly  1,040,250,000  tons. 

Dr.  Livingstone  describes  rivers  of  moving  sand.  [  Travels  in  S.  Africa, 
p.  598.]  _ 

IV.  Deposition,  a.  Alluvial  tracts  in  river-bottoms,  b. 
Natural  levees.  c.  Deltas.  d.  Deposits  in  estuaries.  e. 
Bars  at  river-mouths,  f.  Peculiarities  of  Amazonian  deposi- 
tion. 

&— SUBTERRANEAN  WATER. 

i.  Chemical  Action.  A.  Springs.  I.  Ordinary,  a. 
Solvent  power  mainly  due  to  C02  or  alkali,  b.  Remove  cer- 
tain ingredients,  thus  leaving  cavities,  c.  Effect  replacement 
(pseudomorphism),  d.  Emerge  at  surface  as  calcareous,  siliceous 
ox  ferruginous  (chalybeate)  springs,  e.  Leave  deposits  of 
travertine,  stalactite,  etc.  f.  All  rocks  contain  more  or  less 
moisture  originally  abstracted  from  ocean;  average  2.5  per 
cent.  [Hunt,  R.  13,  II,  xxxix,  193;  Durocher,  R.  53,  x,  1853, 
431;  De  Lesse,  ibid.,  xviii,  1861,  64.  Quoted  in  1,  p.  656J. 
II.  Thermal.  [See  E.— SECONDARY  IGNEOUS  AC- 
TION, ante,  p.  32].  a.  Contain  greater  proportion  of  min- 
eral ingredients  than  ordinary  springs,  b.  Commonly  asso- 
ciated with  folds  or  deep  fissures.  c.  Products :  sulphates, 
chlorides,  sulphur,  silica,  etc.  d.  Examples :  Hot  Springs, 
Arkansas ;  Bath  Springs,  Camp  Brown,  Wyo. ;  warm  springs 
of  Bath,  England,  etc. ;  deep  artesian  wells.  B.  Streams. 
a.  Same  chemical  effects  as  in  springs,  but  on  larger  scale,  as 
in  Mammoth  Cave,  Ky.,  etc. 

2.  Mechanical  Effects.  I.  Caverns,  a.  Most  common 
in  limestone  regions,  b.  Formed  by  corrosion  and  erosion  on 
part  of  underground  streams,  c.  Examples  of  streams  and 
caves : 


42  GENERAL  GEOLOGY. 

(i)  In  central  Penn.  and  elsewhere  large  creeks  frequently  sink  sudden- 
ly and  reappear  miles  beyond ;  in  same  region  are  numerous  caves. 

(2)  Mammoth  Cave,  Ky.,  represents  portions  of  ancient  and  modern 
channels  of  Green  River,  the  several  chambers  and  passages  lying  one 
above  another,  the  whole  system  being  comprised  within  comparatively 
narrow  limits  horizontally.  Numerous  other  caverns  in  vicinity.  Echo 
River  and  Styx  still  connect  with  Green  River. 

(3)  Basins  of  extinct  thermal  springs,  Yellowstone  Park,  afford  some 
fine  examples  of  large  caves. 

d.  Special  features  of  Mammoth  Cave  and  vicinity,  as  il- 
lustrating cave-history  in  general. 

(1)  Slalactitic  formations  scarce  in  main  cave,  and  mainly  confined  to 
certain  chambers,  an  effect  due  to  protection  of  limestone  by  sandstone 
capping,  preventing  free  access  of  water;  (2)  in  domes,  where  fissures  ex- 
ist, water  enters  freely  and  forms  stalactite,  finally  choking  up  the  cavity; 
(3)  same  effect  in  adjacent  caves  with  no  sandstone  capping;  (4)  domes 
in  Mammoth  generally  formed  by  subsidence  of  roof  of  cave. 

II.  Sink-holes,  a.  Basin-like  depressions  in  surface  rocks 
produced  by  falling-in  or  yielding  of  roofs  of  caverns,  b.  Very 
common  and  remarkably  large  in  parts  of  Ky.  ("Cavern  lime- 
stone" of  Owen),  and  general  in  other  regions.  III.  Land- 
slides,    a.  Produced  in  several  ways  : 

(1)  By  slipping  of  wet  soil  held  together  by  trees,  etc.,  as  in  cases  of 
slide  of  Aug.,  1826,  on  White  Mts.  and  rather  frequent  landslips  in  Rocky 
Mountain  region. 

(2)  Inclined  strata,  underlaid  by  soft  layers,  often  glide  down  over  sub- 
jacent beds,  particularly  on  steep  mountain  slopes,  as  in  the  destructive 
slide  of  the  Rossberg,  Switzerland,  1806,  and  in  other  recorded  cases  [R. 
46,  vol.  i]. 

(3)  In  horizontal  strata  underlaid  by  wet  clay,  pressure  may  be  sufficient 
to  displace  latter  and  allow  superincumbent  mass  to  subside,  as  commonly 
occurs  on  shores  of  L.  Erie  and  elsewhere,  and  occasionally  at  points  on 
Hudson  River. 

b.  Slides  cause  scratching  and  polishing  of  rocks  beneath, 
and  sometimes  produce  contortions  in  clayey  layers.  IV.  Mud- 
lumps,  a.  Low  heaps  noticed  near  mouth  of  Mississippi,  b. 
Produced  by  pressure  upon  layer  of  mud  beneath  surface  de- 
posits [Hilgard,  R.  13,  III,  i]. 

J).— FROST,  SNOW  AND  ICE. 

i.  Action  of  Frost,  a.  Expansion  of  water  from  39^° 
F.  to  320  F.  produces  remarkable  mechanical  effects  [see  R. 
96-98].  b.  Explains  absence  of  talus  at  foot  of  cliffs  in  trop- 
ics,    c.  Examples  from  various  localities. 

2.  Snow.  a.  Protects  land  from  erosion,  b.  Very  de- 
structive in  sliding  masses  {avalanches),  c.  Holds  back  pre- 
cipitated moisture  to  cause  increased  destruction  by  rapid  melt- 
ing. 

3.  Glaciers  [R.  92,  96-103].     I.   General  Character,     a. 


SURFACE  AGENCIES.  43 

Ice-streams  descending  valleys  below  snow-line.  b.  Exist  only 
in  regions  of  abundant  precipitation  where  mountains  extend 
above  limit  of  perpetual  snow  and  where  alternate  freezing  and 
thawing  occur,  c.  Mainly  confined  to  higher  latitudes,  d. 
Occupy  transverse  valleys  of  erosion.  II.  Structure,  a. 
Veins;  marginal,  transverse  and  longitudinal,  b.  Crevasses; 
marginal,  transverse,  longitudinal,  c.  Moraines;  lateral  and 
terminal,  d.  "  Glacier  tables."  III.  Motion,  a.  Rate  varies 
from  1  in.  to  60  ft.  per  day.  b.  Rate  varies  according  to  :  (1) 
amount  and  frequency  of  precipitation;  (2)  obstructions  in 
valley ;  (3)  slope  of  surface ;  (4)  point  of  observation,  c. 
Laws : 

(1)  Velocity  greatest  along  median  line,  as  in  water-streams.  [Friction 
against  sides.] 

(2)  Motion  most  rapid  at  top,  least  at  bottom.  [Atmospheric  friction  not 
appreciable  ] 

(3)  Velocity  increases  directly  as  angle  of  slope. 

(4)  Motion  varies  with  thickness  (depth  of  stream). 

(5)  Degree  of  fluidity  materially  affects  progress.  [Summer  and  winter 
changes]. 

(6)  Rate  of  flow  in  tortuous  channels  follows  laws  of  river-motion,  except 
that  greater  viscosity  of  ice-sheet  overcomes  greater  resistances. 

d.  Theories  of  glacier-motion  : 

(1)  Forbes'  Theory  regards  ice  as  viscous-brittle  substance  flowing  under 
its  own  weight,  on  principle  of  slowly  applied  pressure. 

(2)  TyndalPs  Theory  of  ttflracture  and  regelation?'1  based  on  fact  that 
slow  pressure  in  small  masses  causes  fracture,  while  fragments  are  re- 
united by  pressure. 

IV.  Transportation,  Erosion,  Deposition,  a.  Effects  much 
greater  than  in  case  of  water,  owing  to  buoyant  action  of  ice, 
and  greater  resistance  opposed  to  obstructions,  b.  Transpor- 
tation of  material,  c.  Grooving  and  polishing  of  strata,  d. 
Rounded  hills,  roches  moutonnees,  parallel  valleys,  etc.  e.  En- 
largement of  valleys,     f.  Formation  of  "  Drift "  deposits. 

4.  Icebergs,  a.  Fragments  broken  from  lower  end  of 
glacier  by  buoyant  power  of  water,  etc. 

Sp.  gr.  of  ice  =0.918  (320  F.),  hence  exposed  mass  of  iceberg  is  about 
T^-  of  total  weight,  when  solid.  Actually  nearly  \  above  water,  and  some 
icebergs  300  ft.  visible. 

b.  Effects;  scoring  of  rocks  (irregularly),  erosion  of  gullies, 
deposits  of  boulders. 

5.  Anchor-ice  and  Shore-ice.  a.  Produce  effects  of 
some  importance  occasionally. 

Ref. : — 1  (pp.  635-696),  2  (chaps,  xxiii-xxv),  3 
(pp.  9-76),  4-6,  8-1 1,  23,  27,46,  55  (pp.  155- 
167),  56  {Index,  water),  57  (vol.  i),  68,  69,  87, 
92—103,  106,  118,  119. 


44  GENERAL  GEOLOGY. 

DIVISION  B.— ATMOSPHERIC  ACTION. 

i.  Protective,  a.  Preservation  of  human  works  and 
other  remains  by  blown  sand. 

2.  Formative,  a.  Production  of  soil  (and  boulders)  by- 
disintegration  of  rocks,  as  in  "driftless"  regions,  b.  Trans- 
portation of  seeds  by  wind.  c.  "Dust-showers"  and  "blood- 
rains"  [R.  13,  (II,  xi,  p.  372),  105].     d.  Sand-hills,  dunes,  etc. 

3.  Destructive,  a.  Weathering  of  rocks,  b.  Effects  of 
wind : 

(1)  Erosion  of  rocks,  as  by  sand-blast,  in  Colorado  and  elsewhere;  (2) 
obliteration  of  land-marks  by  shifting  sands ;  (3)  denudation  of  sand-fLts 
and  hummocks  where  not  protected  by  vegetation  ;  (4)  overthrowing  of 
forest  trees. 

c.  Atmospheric  electricity;  fulgurites  [R.  48,  vol.. II,  1814, 
p.  528J.  d.  Ozone  in  windy  localities,  as  near  S.  Pass,  Wyo. 
[R.  55,  p.  178J.  e.  Marked  variations  in  atmospheric  pressure 
causing  fluctuations  in  level  of  Great  Lakes.  [See  Col.  Chas. 
Whittlesey's  papers  in  R.  78,  1873  (B,  p.  42),  1874  (A,  p.  139), 
and  in  Canadian  Naturalist,  April,  1875.] 

Ref. :— 1  (pp.  630-635),  2  (chap,  xxi),  3  (pp. 
3-8),  4-6,  8-1 1,  23,  35,  41,  46,  47,  68,  84,  87, 
90  (1867),  91  (1867),  105,  107  (chap,  vi),  108. 

DIVISION  C— ACTION  OF  LIFE. 

A.—  VEGE  TA  TION. 

i.  Protective  Influences,  a.  Turf,  roots  of  trees,  etc., 
bind  soil  and  prevent  erosion  to  some  extent  [special  cases,  R. 
55,  pp.  170-173]- 

2.  Deposits  of  Peat.  a.  Most  common  in  northern  re- 
gions, where  climate  is  moist,  as  in  Ireland,  N.  U.  S.,  etc.  b. 
Formed  from  mosses  [sphagnum,  Hyptium,  etc.),  and  sometimes 
from  other  plants,  as  in  Dismal  Swamp,  N.  Car.  (from  leaves). 
C.  Peat-bogs  commonly  antiseptic,  d.  Similar  formations  in 
Central  N.  Y.  e.  Bogs  probably  ordinarily  originate  from 
prostration  of  timber,  f.  Coal  results  from  decomposition  and 
more  or  less  complete  metamorphism  of  peat,  or  more  often  of 
woody  tissue. 

3.  Drift-wood  Accumulations,  a.  Represented  by 
famous  Red  River  and  other  "  rafts." 

4.  Bog-iron  Ore  Deposits,     a.  Produced  by: 

(1)  Deoxydation  of  Fe503  in  presence  of  decaying  organic  matter;  (2) 
combination  of  resulting  FeO  with  nascent  Co.2,  and  (3)  final  conversion 
of  FeCOj,  by  oxydation,  into  Fe203,  3H20  {limonile). 


SURFACE  AGENCIES.  45 

5.  Destructive  Effects,  a.  Through  force  exerted  by 
growing  roots  in  crevices,  b.  Vegetation  holds  back  moisture 
in  soil,  thus  facilitating  disintegration,  c.  Landslides  rendered 
more  destructive  by  binding  effect  of  trees  and  turf.  d.  Dam- 
age increased  in  tornados,  etc.,  by  overthrow  of  trees. 

B.— ANIMAL  FORMATIONS,  ETC. 

i.  Siliceous  Deposits  [ante,  p.  15].  a.  Ehrenberg's  es- 
timate : 

(1)  17,946  cu.  ft.  of  siliceous  organisms  annually  forming  in  one  harbor 
in  Baltic ;  (2)  he  collected  from  the  mud  one  pound  in  one  hour  =  700, 
000,000,000  individuals;  (3)  his  estimate  of  increase  of  single  individual 
for  one  month  =  enough  to  form  bed  of  silica  of  18,480,000  cu.  ft.  =more 
than  1,600,000,000,000,000,000,000  individuals. 

b.  Commonly  found  segregated  in  layers  or  nodules  (chert, 
flint,  etc.)  c.  In  all  parts  of  the  ocean  and  even  living  in  ice. 
d.  Some  noted  accumulations  : 

(i)  Polycystine  sandstone,  Barbadoes  ;  (2)  Polycystine  deposits,  Sea  of 
Kamtchatka  [R.  13,  II,  xxii,  PI.  I],  Nicobar  Is.  (100  species,  Ehr.),  Bar- 
badoes (282  sp.,  Ehr.) 

2.  Oaze,  Marls  and  Shell-Deposits,  a.  More  CaCOj 
in  rivers  than  in  ocean ;  abstracted  from  latter  by  organisms : 

(1)  Foraminiferal  remains  make  up  bulk  of  deep-sea  ooze  and  finally 
produce  chalk. 

(2)  Shells  of  Mollnsca  in  ponds  or  near  shores  of  lakes  and  seas  form 
marls  (as  near  Cortland  and  Cayuga  in  N.  Y.  State),  and  these  and  corals 
after  attrition  and  comminution  by  waves,  produce  oolyte. 

3.  Coral  Reefs  and  Coral  Islands,  a.  Distribution 
of  reef-builders : 

(1)  Limited  by  "isocryme"  of  68°  F.,  averaging  Lat.  300  N.  and  S. , 
[on  W.  coast  of  Africa  and  E.  coast  of  Asia  forced  back  to  Lat.  15°,  W. 
N.  Amer.  to  23^°,  by  cold  currents,  and  on  E.  coasts  of  Africa  (Cape  of 
Good  Hope)  and  N.  America  (Bermuda)  extended  to  nearly  320  by  warm 
currents]  ;  (2)  cannot  grow  in  water  deeper  than  100  ft. ;  (3)  require  clear 
salt  water;  (4)  most  kinds  flourish  best  in  rough  water;  (5)  volcanic 
action  prevents  growth. 

b.  Formation  of  "fringing  reefs"  about  islands,  c.  "Barrier 
reefs." 

(1)  Formed  outside  of  fringing  reefs,  leaving  channel  between  of  vary- 
ing dimensions  (from  very  shallow  and  narrow  to  considerable  depth,  and 
breadth  of  even  60  miles) ;  (2)  channel  kept  open  by  fresh-water  streams, 
tidal  and  local  currents  or  depth  of  water. 

d.  "  Atolls,"  or  coral  islands  : 

(1)  Formed  by  growth  of  corals  to  low-tide  level;  (2)  then  by  wave- 
action,  irregular  encircling  reef  is  raised  about  a  central  "lagoon";  (3)- 
vegetation  finally  grows  from  transported  seeds;  (4)  small  atolls  some- 
times fill  up  lagoon. 

e.  Kinds  of  coral  rocks  [R.  1,  p.  620]. 


46  GENERAL  GEOLOGY. 

(i)  Compact,  tough  limestone,  non-fossiliferous ;  (2)  compact  oolyte, 
generally  non-fossiliferous;  (3)  like  (1),  but  with  fragments  of  shells  and 
corals  imbedded  ;  (4)  coarse  conglomerate  of  firmly  cemented  masses  of 
coral;   (5)  corals  in  situ,  with  interstices  filled  in  with  sand,  mud,  etc. 

4.  Theories  of  Atolls  and  Barrier  Reefs.  A.  State- 
ment, a.  Often. extend  to  enormous  depths,  while  corals  can- 
not live  below  cir cum- littoral  zone  (ante  p.  10).  b.  Formerly 
explained  by  crater  theoiy,  but  Darwin's  subsidence  theory  now 
commonly  received : 

( 1 )  Crater  Theory.  Regards  atoll  as  built  upon  rim,  lagoon  as  occupy- 
ing basin,  of  extinct  volcanic  crater. 

(2)  Theory  of  Stibsidenee  [C.  Darwin,  R.  48  (1840,  pp.  505-510),  65 
(vol.  xii,  pp.  115-119),  66  (II,  1838,  p.  552),  84  (pp.  465-482),  86  (lxiv, 
1845,  p.  563),  ill;  Dana,  R.  109,  also  1;  outline  of  argumetit  in  R.  2 
(PP-  335'  336)>  3  (P-  144  et  seq.)\  Supposes  gradual  subsidence  of  fring- 
ing reef  and  inclosed  island,  not  more  rapid  than  growth  of  corals,  on 
average,  and  at  no  time  during  its  formation  submerging  reef  more  than 
100  ft. 

B.  Discussion.  I.  Crater,  a.  Submarine  banks,  probably 
offering  conditions  suitable  for  atoll  growth,  are  sometimes  pro- 
duced by  volcanic  action,  b.  Barrier  reefs,  though  of  similar 
origin,  not  explained  by  this  theory,  c.  Atolls  more  extensive 
(even  10  mi.  to  90  mi.  wide)  and  more  precipitous  (5o°-6o°) 
than  volcanic  cones.  II.  Subsidence,  a.  Accounts  for  barrier 
reefs  and  all  features  of  atolls,     b.  Lyell's  early  views : 

In  1st  edition  of  "Principles"  states  that  amount  of  subsidence  in  Pacific 
is  greater  than  elevation,  as  area  of  land  is  small  compared  with  formative 
agents  (coral-growth  and  volcanic  action). 

c.  Evidences  of  subsidence  given  by  nearly  all  travelers 
among  coral  islands  of  Pacific,  d.  This  theory  explains  ab- 
sence of  corals  from  an  area  of  2,000,000  sq.  mi.  in  mid-Pacific, 
where  all  conditions  are  favorable  except  depth. 

C.  Remarkable  Exceptions,  a.  Florida  reefs,  occupying 
lower  half  of  State  (20,000  sq.  mi.),  example  of  increase  of  land. 
b.  No  evidence  of  subsidence  or  of  growth  about  volcanic 
area.  c.  Probable  agency  of  Gulf  Stream  [see  Leconte  (R. 
3,  pp.  149-153)  for  admirable  statement  and  argument]. 

5.  Rate  of  Growth  of  Coral-formations,  a.  Average 
increase  in  height  less  than  .10  in.  (Dana's  estimate  .0625  in.) 
per  annum  =120  yrs.  per  ft.  b.  Some  existing  deposits  (now 
growing)  fully  2000  ft.  thick,  have  required  from  240,000  yrs. 
to  384,000  yrs.  c.  With  subsidence  more  gradual  than  growth- 
rate,  time  would  be  increased  proportionately. 

Ref. : — 1  (pp.  606-626),  2  (chap,  xxii),  3  (pp. 
^-^SX  4-6,  8-1 1,  13,  27,  28,  36,  41,  46, 
47,  68,  69,  84,  105,  108-113,  120. 


S  URFA  CE  A  GEN CIES.  47 * 

SECTION  III  -M0RPH0GONY  (Supplementary).1 

1.  Hills  and  Mountains,  a.  Relations  of  form  to  struct- 
ure illustrated,  b.  Hills  of  upheaval;  characteristic  forms,  c. 
Hills  of  deposition,  how  produced,  d.  Hills  of  circum-denu- 
dation.     e.  "Outliers"  and  "escarpments." 

2.  Plains  and  Plateaus,  a.  Plains  of  deposition,  b. 
Plains  of  denudation,     c.  Table-lands. 

3.  Valleys  and  Ravines,  a.  Of  erosion,  b.  Of  de- 
pression, c.  Formed  by  circum-deposition.  d.  Longitudinal 
valleys  [R.  94,  p.  160,  figs.  55,  56,  58]:  (1)  synclinal ;  (2) 
monoclinal ;  (3)  anticlinal,  e.  Transverse  valleys  [R.  94,  p. 
160,  figs.  53,  54,  57] :  (1)  cataclinal ;  (2)  anaclinal ;  (3)  dia- 
clinal. 

4.  Lakes  and  Ponds,  a.  In  basin  of  erosion  or  of  cir- 
cum-deposition. b.  Dammed-up  by  superficial  deposits,  caused 
by: 

(1)  Streams  of  lava  ;  (2)  terminal  moraines  of  glaciers  ;  (3)  land-slides  ; 
(4)  sand-bars  drifted  ;   (5)  irregular  deposition  ;   (6)  work  of  beavers. 

5.  Mountain  Passes,  a.  Produced  by  erosion,  b.  Re- 
sult of  faults,     c.  Synclinal  passes  (depressed). 

6.  Fjords,  or  Sea-lochs,  a.  Generally  regarded  as 
former  glacial  valleys,  now  partially  submerged. 

7.  Caverns,  a.  Subterranean  (already  discussed),  b. 
Along  sea-coasts,  c.  From  landslides  or  tumbling  of  large 
masses  from  cliffs. 

8.  Cliffs,     a.  Of  erosion,     b.  Of  displacement. 

9.  Canons,  Alcoves  and  Amphitheatres,  a.  Gen- 
eral remarks. 

Ref.  : — 2,  chap,  xxvi,  is  admirable ;  Powell,  R. 
94,  gives  very  much  valuable  and  interesting 
description  of  valleys,  canons,  alcoves,  cliffs,  etc. 

1  It  would  be  quite  proper  under  this  head  to  discuss  several  subjects,  such  as  Mount- 
ain Elevation,  Special  Forms  of  Erosion  above  and  below  surface,  Fornlation  0/  Coral 
Islands,  etc.,  but  each  of  these  has  already  been  considered  in  a  more  convenient  place. 


48  GENERAL  GEOLOGY. 

PART  V.-PALiEONTOLOGY. 

I.  Definitions  and  Divisions,  a.  Literally,  discourse 
about  ancient  beings,  b.  As  here  restricted,  treats  mainly  of  ex- 
tinct forms  of  life  preserved  as  fossils  and  of  their  relations  to 
existing  plants  and  animals.1 

BIVISION  A.-BIOLOGICAL  RELATIONS. 

I.  Convenient  Classification  of  Plants  and  Ani- 
mals.     A.    Vegetable    Kingdom.2      I.    Cryptogamia.      a. 

Multiplying  by  spores  containing  no  embryo,  b.  Subdivisions: 
Class  I. — Thallogens.  Fronds  spreading,  commonly  with  no  dis- 
tinct axis;  composed  wholly  of  cellular  tissue.  Sub-class  I. — ALG/E. 
Ex.  :  Fucoids  (leathery  sea-weeds),  Confervacea:,  Dialomacece,  Coral- 
lines, Coccoliths,  Nullipores.  Sub-class  II. — Mycetales.  Ex.  : 
Lichens,  Fungi. 
Cla.SS   II* — Anogens.      Cellular  tissue,  with  short,  leafy  axis  more 

or  less  developed.     Ex.  :  Mosses,  Liverworts. 
Class    III* — Acrogens.      Vascular  tissue,  in    part,   growing  from 
apex;  ascending  and  descending  axes  prominent.     Ex.  :  Ferns,  Tree- 
ferns,  Lycopods,  Equisetacece. 

II.  Phanerogamia.  a.  Distinct  flowers;  multiplying  by 
seeds  containing  embryo,     b.  Subdivisions : 

Class  I. — Endogens.  Single  cotyledon,  endogenous  in  growth. 
Division  I. — Glumace^E.  Ex.  :  Grasses,  Sedges,  Reeds,  etc.  DIVI- 
SION II. — Petaloide^:.     Ex.  :  Palm,  Lily,  Banana,  etc. 

Class  II. — GymnosperMS.  Often  polycotyledonous,  exogenous, 
seeds  naked.  Division  I. — Conifer/E.  Ex.  :  Pine,  Fir,  Cypress, 
Cedar,  Araucaria-.  Division  II. — Cycade.'E.  Ex.  :  Cycads  (Palm- 
like and  acrogenous). 

Class  III. — Angiosperms.  Dicotyledonous,  exogenous,  enclosed 
seeds.  Division  I. — Monochi.amyde>e  (Apetalous).  Ex.  :  Oak, 
Beech,  Birch,  Walnut,  Chestnut.  Division  II. — Corolliflor/E 
(Monopetalous).  Ex. :  Ash,  Thistle,  Honeysuckle,  Rhododendron. 
Division  III. — Calyciflor^:  (Polypetalous,  stamens  perigynous). 
Ex.  :  Rose,  Apple,  Pear,  Cherry,  Cactus,  Hemlock.  Division  IV. — 
Thalam  I  florae  (Polypetalous,  stamens  hypogynous).  Ex.:  Maple, 
Balsam,  Mahogany,  Orange,  Tea,  Geranium. 

B.  Animal  Kingdom.3     I.  Protozoa,     a.   Simple  or  com- 

1  In  the  present  course  of  lectures,  this  subject  is  meiely  outlined  as  a  necessary  intro- 
duction to  Historical  Geology  (Part  VI). 

1  This  outline  scheme  of  the  Vegetable  Kingdom  is,  in  part,  based  upon  a  "Synopsis" 
prepared  several  years  ago  by  Dr.  W.  H.  Harvey  for  Professor  Jukes  (published  in  R.  2, 
p.  760),  but  several  quite  important  modifications,  with  fuller  descriptions,  are  here  in- 
troduced. 

3  The  main  features  of  this  outline  scheme  of  the  Animal  Kingdom  correspond  to 
Professor  Huxley's  published  systems,  with  certain  modifications,  not  material,  intro- 
duced merely  for  the  purposes  of  this  course  of  lectures.  Duly  qualified  members  of  the 
class  should  require  such  a  scheme  only  as  a  check  upon  the  memory.    Those  who  have 


PALjE  ONTOLOG  Y.  49 

pound,  generally  minute,  b.  Body  composed  of  structureless 
"sarcode."     c.  Subdivisions: 

Class  I. — Rhizopods.  Possess  power  of  prolonging  sarcode  in 
shape  of  pseudopodia;  fossil  forms  protected  by  calcareous  or  sili- 
ceous "test."  Order  i. — Foraminifera.  Ex.  :  Nummulites, 
Urbitoides,  Fusulina,  Eozoon.  Order  2. — Radiolaria.  Ex.  :  Poly- 
cyslina  (various). 
Class  II. — Sponges.  Compound;  sarcode  supported  by  net-work 
of  siliceous  or  calcareous  spicules. 

II.  Ccelenterata.  a.  Body  composed  of  2  layers,  b.  ali- 
mentary canal  communicating  freely  with  body-cavity.  c. 
Subdivisions : 

Class  I. — Hydrozoans  (Acalephs).  Digestive  tract  and  body-cavity 
coincident.  Order  i. — Tubularida  (Corynida).  Order  2. — 
Sertularida.  Order  3. — Graptolitid.^e.  Ex.  :  Graptolites  (ex- 
tinct),    [^//fossil  forms  are  of  Sub-class  I. — Hydrophora]. 

Class  II. — Actinozoans.  Digestive  sac,  opening  below  into  cham- 
bered body  cavity  with  radiating  septa.  Order  i. — Zoantharia. 
Corallum  sclerodermic  (occasionally  sclerobasic)  ;  tentacles  simple, 
multiple  of  5  or  6.  Ex. :  Aladrepores,  Star-corals,  Brain-corals. 
Order  2. — Alcyonaria.  Corallum  sclerobasic;  tentacles  fringed, 
multiple  of  4.  Order  3. — Rugosa  (all  extinct).  Corallum  sclero- 
dermic; parls  in  multiples  of  4,  transverse  tabulae  commonly  uniting 
septa. 

III.  Mollusca.  a.  Body  soft,  commonly  covered  by  a 
shell,  b.  Heart  (when  present)  on  dorsal  aspect,  nervous  sys- 
tem in  one  ganglion,  or  scattered  pairs,     c.  Sub-divisions  : 

PROVINCE  A. — Molluscoida.  Heart  absent  or  imperfect; 
single  ganglion  or  one  pair  of  ganglia. 

Class  I. — Poi.YZOANS  (Bryozoans).  Compound,  generally  not  con- 
nected internally  ;   2  coats  ;   retractile  muscle.     5  Orders. 

Class  II. — Tunicates  (Ascidians).  Simple  or  compound  ;  leathery 
"test,"  lined  by  muscular  coat;  2  anterior  openings  ;  respiratory  sac  ; 
simple,  open  tubular  heart;   one  ganglion,  orally  placed. 

Class  III. — Brachiopods.  Simple;  shell  bivalve  {ventral  and  dor- 
sal) ;  inequivalve  (ventral  v.  usually  larger),  opened  and  closed  by 
muscles,  commonly  fixed  by  muscular  stalk  passing  through  aperture 
in  beak  of  ventral  v. ,  or  between  valves  or  attached  to  substance  of 
ventral  v. ;  2  fringed  arms  about  mouth,  commonly  coiled,  supported 
by  framework.  Order  1. — Inarticulata.  Ex.  :  Lingula,  Crania, 
Discina.  Order  2. — Articulata.  Ex.  :  Terebralula,  Spirifera, 
Ori/iis,  Producla,  Rkynchonella,  Athyris. 

PROVINCE  JB. — Mollusca  Proper.  Nervous  system,  3  pairs 
of  ganglia,  heart  with  at  least  2  chambers. 

Class  IV. — Lamellibranchs.  Bivalves,  shells  equivalve  (usually), 
inequilateral,  closed  by  muscles,  opened  by  ligament;  respiration  by 
lamellar  branchiae  (gills).     Ex.  :  Oyster,  Clam,  etc. 

Class  V. — Gasteropods.     Shell  (when  present)  never  bivalve  ;  oc- 

little  or  no  familiarity  with  zoology  will  find  all  necessary  information  upon  this  subject 
in  either  one  of  R.  114,  115,  or  116.  \N.  B. — Only  such  groups  as  are  0/ geological  im- 
portance are  here  given.] 


50  GENERAL  GEOLOGY. 

casionally  multivalve,  commonly  univalve,  whorled  more  or  less 
spirally.   Sub-class  I. — Branchifera.    Respiration  by  gills,  aquatic. 

7  Provisional  Orders.  Ex.  :  Limpet,  Whelk,  Periwinkle.  Sub- 
class II. — Pulmonifera.  Aerial  respiration  by  pulmonary  sacs  ; 
terrestrial  or  amphibious.  Order  I. — Operculata.  Order  2. — 
Inoperculata. 

Class  VI. — Pteropods.  Winged  appendages  at  mouth,  for  swim- 
ming.    Large  forms  extinct. 

Class  "VII. — Cephalopods.  External  shell  (if  present)  usually 
chambered,  straight  or  coiled  in  a  plane,  siphuncle  passing  through 
partitions.  Order  i. — Dibranchiata.  2  gills,  10  arms  or  less, 
with  suckers ;  little  or  no  external  shell.     Sub-order  i. — Octopoda. 

8  arms.  Ex.  :  Octopus,  Paper  Nautilus.  Sub-order  2. — Deca- 
PODA.  10  arms.  Ex.  :  Squid,  Calamary.  Order  2. — Tetra- 
BRANCHIATA.  4  gills  ;  arms  more  than  10,  without  suckers  ;  exter- 
nal, many  chambered  shell.      Ex.  :  Orthoceras,  Ammonite,  Goniatite. 

IV.  A?inuloida.  a.  Alimentary  canal  entirely  distinct  from 
body-cavity,  b.  "Water-vascular"  system  present,  c.  Sub- 
divisions : 

Class  I. — Echinoderms.  Ambulacral  system  communicating  with 
exterior,  commonly  employed  in  locomotion  ;  integument  of  calcare- 
ous plates  or  leathery,  with  imbedded  grains,  spines  or  tubercles. 
Order  i. — Crinoidea. — Fixed  (almost  always)  by  jointed  stem; 
central  cup  or  disk  of  calcareous  plates  with  5  or  more  radiating  (often 
branching)  arms  from  margin.  Order  2. — Blastoidea  (Pentre- 
mitids).  Attached,  body  ovoidal;  5  petaloid  ambulacra  meeting  at 
summit,  no  true  arms.  Order  3. — Cystoidea.  Plates  not  regularly 
radiated;  arms  absent,  rudimentary  or  few,  not  marginal;  "pectin- 
ated rhombs"  bet.  ambulacral  areas.  Order  4. — Asteroidea. 
Star-shaped;  central  disk  with  5  or  more  arms  radiating,  containing 
prolongations  of  stomach;  integument  leathery.  Ex.:  Star-fish. 
Order  5. — Ophiuroidea.  Central  disk  covered  with  calcareous 
plates  ;  arms  locomotive  and  prehensile,  without  internal  prolonga- 
tions of  stomach.  Ex.  :  Brittle  stars.  Order  6. — Echinoidea. 
Body  spherical  to  discoidal ;  covered  by  test  jointed  immovably 
(mostly).  Order  7. — Holothuroidea.  Leathery,  etc.  (recent 
and  fossil  forms  rare). 

V.  Annalosa.  Articulated  body;  limbs  (when  present) 
turned  towards  side  on  which  nervous  system  predominates. 

PROVINCE  A. — Anarthropoda.  Limbs,  when  present,  not 
jointed  or  articulated  to  body. 

Class.  I — Annelids.  Body  segmented,  with  lateral  appendages  of- 
ten in  pairs.  Order  i. — Tubicola.  Branchiate,  secreting  mem- 
branous or  calcareous  tube.     Ex.  :  Serpula,  Spirorbis. 

PROVINCE  15. — Arthropoda.    Articulated,  jointed  appendages. 

Class  II. — Crustaceans.  More  or  less  aquatic;  2  prs.  antennae; 
limbs  on  thorax  and  abdomen  (usually).  Order  i. — Decapoda 
(Podophthalmia).  5  prs.  legs,  eyes  stalked.  Sub-order  i. — Ma- 
crura.  Tail  well  developed,  long.  Ex.  :  Lobster.  Sub-order  2. 
— Brachyura.  Tail  short  and  turned  under.  Ex.  :  Crab.  Order 
2. — Isopoda.  Head  distinct,  eyes  sessile.  Ex.  :  Wood-lice.  Or- 
der 3. — Merostomata.     Legs  about  mouth  used  as  jaws,  paddles, 


PALEONTOLOGY.  51 

etc.     Ex.  :  Limulus,  Eurypterus.      Order  4. — Trilobita.     Body- 
divided  laterally  into  3  lobes.    Order  5. — Cirripedia  (Pectostraca). 
Multivalve  shell.     Ex.  :  Barnacle,  Acorn-shell.     Order  6. — Ostra- 
CODA.     Bivalve  shell.     Ex.  :  Cypris.  etc. 
Class  III. — Arachnids.     Head  and  thorax  united  (cephalo-thorax)  ; 
terrestrial;   legs  never  exceeding  4  prs.,  none  on  abdomen.     Ex.: 
Spiders,  Scorpions. 
Class  IV. —  Myriapods.     Head  distinct,  thorax  not  distinct  from 
abdomen ;   segments  more  than  20  (one  exception) ;   legs  more  than 
8  prs.  ;   one  pr.  antennae.     Ex.  :  Centipede,  Millipede. 
Class  V. — Insects.      Head,  thorax  and  abdomen  distinct;  legs  (on 
thorax)    never   more  than  3  prs.     Order   i. — Hemiptera.     Ex.: 
Cicada,  Aphis.     Order  2. — Orthoptera.     Ex.  :  Cricket,  Locust, 
Grasshopper.     Order  3. — Neuroptera.    Ex.  :  Dragon-fly,  Caddis- 
fly.     Order  4. — Diptera.     Ex.  :  Ely,  gnat.     Order  5. — Lepid- 
uptera.    Ex.  :  Butterfly,  Moth.     Order  b. — HYMENOPTERA.    Ex.  : 
Wasp,  Bee,  Ant.     Order  7. — Coleoptera.     Ex.  :  Beetle. 
VI.    Ve?'tet>rata.     Body  of  definite  segments ;  often  an  exo- 
skeleton  of  scales  or  bony  plates ;  limbs  ventral,  turned  away 
from  side  on  which  nervous  system  predominates.     Vertebral 
column  (cartilaginous  or  osseous)  usually  present  in  adult. 

PKOVlftCfi  A. — Ichthyopsida.     Branchiae  present  permanently 
or  at  least  during  tirst  stages  of  growth. 

Class  I. — Fishes.  Group  illy  defined;  median  fins  (interspinous) 
probably  always  present,  and  always  provided  with  fringe  of  fin-rays, 
as  are  paired  fins.  Order  I. — Marsipobranchii.  Skull  and  ver- 
tebral column  cartilaginous  ;  mandible  and  cranial  bones  wanting ;  no 
clavicle,  no  limbs ;  gills  saccate,  non-ciliated.  Ex. :  Lamprey. 
Order  2. — Elasmobranchii.  Skull  well  developed,  vertebral  col- 
umn varying ;  mandible  present,  no  cranial  bones  ;  no  clavicle,  2  prs. 
fins,  supported  by  multiple  cartilages  ;  gills  pouched.  Ex. :  Shark, 
Ray.  Order  3. — Teleostei.  Skeleton  bony,  as  in  modern  fishes  ; 
vertebral  column  more  or  less  completely  ossified;  clavicle,  2  prs. 
fins,  ventral  varying  in  position;  guls  tufted  or  pectinate,  protected 
by  bony  coverings.  Ex.  :  Perch,  Cod,  Salmon.  Order  4. — Ga- 
NOIDEI.  Osseous  skull ;  vertebral  column  varying;  clavicle  present, 
2  prs.  fins,  posterior  near  anus.  Order  5. — Dipnoi.  Skull  bony, 
vertebral  column  cartilaginous  ;  clavicle,  2  prs.  filiform  fins,  each  sup- 
ported by  jointed  cartilaginous  rod;  posterior  pr.  close  to  anus.  Ex.  : 
Lepidosiren. 
Class  II. — Amphibians.  Median  fins,  when  present,  not  fringed 
with  fin-rays  ;  2  occipital  condyles  ;  basi-occipiial  unossified.  Order 
I. — Labyrinthodonta.  Salamandroid  body,  weak  limbs,  long  tail; 
skull  somewhat  as  in  Fishes  ;  dorsal  vert,  bi-concave ;  teeth  "labyrin- 
thine "  in  cross  section.  Order  2. — Ophiomorpha  (Gymnophiona). 
Worm-like  body,  no  limbs  or  tail ;  scales  imbedded  in  integument ; 
dorsal  vert,  bi-concave.  Ex.:  Ccecilia,  etc.  Order  3. — Batrachia 
( Anoura).  Exoskeleton  absent  or  represented  rarely  by  dorsal  derm- 
al ossifications;  dorsal  vertebrae  proccelous  (concavo-convex),  ribs 
rudimentary;  radius  united  with  ulna,  tibia  with  fl  bu  la.  Ex.:  Frog, 
Toad.  Order  4. — Urodela.  No  exoskeleton;  dorsal  vert,  am- 
phiccelous  (bi-concave)  or  opisthoccelous  (convexo-concave),  ribs 
short.     Ex.  :  Newt,  Salamander,  Axolotl  (Siredon),  Siren  (mud-eel). 


52  GENERAL  GEOLOGY. 

PROVINCE  B.— Sauropsida.  No  branchiae  during  life  ;  single 
occipital  condyle  partly  made  up  of  ossified  basi-occipital ;  mandibular 
ramus  complex,  articulated  to  skull  by  quadrate  bone. 

Class  III. — Reptiles.  Horny  exoskeleton  commonly  in  form  of 
broad  plates  or  overlapping  scales ;  flying  apparatus  (when  present) 
not  bird-like.  Order  i. — Ichthyosauria.  Ex.  :  Ichthyosaurus. 
Order  2. — Chelonia.  Ex.  :  Tortoise,  Turtle.  Order  3. — Ophid- 
ia.  Ex.  :  Rattlesnake,  Boa,  etc.  Order  4.— Pythonomorpha. 
Ex.:  Clidastes,  Liodon,  Edestosaurus,  Mosasaurus.  Order  5. — 
Lacertilia.  Ex.  :  Lizard,  Blindworm.  Order  6. — Plesiosauria. 
Ex.  :  Plesiosatirus.  Order  7. — Crocodilia.  Ex.:  Crocodile,  Al- 
ligator, Teleosaurus.  Order  8. — Dicynodontia.  Ex.:  Dicynodon, 
Oudenodon.  Order  9. — Pterosauria.  Pterydactylus,  Rhampho- 
rhyncus.  Order  10. — Dinosauria  (Ornithoscelida).  Ex.  :  Igua- 
nodon,  Megalosaurus,  Scelidosaurus,  Thecodontosaurus,  Poikilo- 
pleuron. 
Class  IV. — Birds  (Aves).  Feathery  covering  produced  by  conver- 
sion of  dermal  cells  into  horn  :  fore-limbs  acting  as  wings,  metacar- 
pal bones  often  anchylosed,  metatarsals  and  distal  tarsal  also  ("tarso- 
metatarsus ").  Order  i. — Saurur^e.  Tail  longer  than  trunk; 
metacarpals  free.  Ex. :  Arclucopteryx.  Order  2. — Ratit/E.  Tail 
shorter  than  trunk  ;  metacarpals  anchylosed  ;  sternum  without  crest. 
Elx.  :  Ostrich,  Emu,  Apteryx,  Dinornis.  Order  3. — Carinat^s. 
Tail  short,  terminated  by  "plough-share"  bone;  metacarpals  anchy- 
losed ;  sternum  with  keel.  Ex.  :  Penguin,  Goose,  Pigeon,  Parrot, 
Eagle,  Heron,  Snipe,  etc.  Order  4. — Dentaive  (Odontornithes 
[Subclass]  Marsh).  Birds  with  teeth.  Sub-order  i. — Odontolc^. 
Vertebrae  as  in  ordinary  birds ;  sternum  without  keel ;  wings  rudi- 
mentary ;  teeth  in  grooves.  Ex.  :  Uespero?-nis  regalis  Marsh.  Sub- 
order 2. — Icjithyornithes.  Vertebra;  bi-concave  ;  sternum  with 
keel  ;  wings  well  developed.  Ex.  :  Jchthyornis  dispar  Marsh. 
PROVINCE  C. — Mammalia.  Hairy  appendages  developed  from 
dermal  cells ;  young  nourished  by  milk  secretion  ;  2  occipital  condyles  : 
ramus  of  lower  jaw  simple,  articulating  directly  with  squamosal  bone. 
Class  V. — Mammalia.1  Characters  of  Province  C.  Order  i. — 
Monotremata.  Ex.  :  Echidna,  Urnilhorhynchus.  Order  2. — 
Marsupialia.  Ex.  :  Opossum,  Kangaroo,  Myrmecobius.  Order 
3. — Edentata.  Ex.  ':  Sloth,  Armadillo,  Megatherium,  Megalotiyx, 
Mylodon,  Glyptodon.  Order  4. — Cetacea.  Ex.  :  Whale%  Zeug- 
lodon,  Squalodon.  Order  5. — SlRENlA.  Ex.  :  Manatee,  Halilhe- 
rium,  Rhylina.  Order  6. — Ungulata.  Sub-order  i. — Peris- 
SODACTYLA.  Ex. ."  Horse,  Tapir,  Orohippus,  Pala'osyops,  Rhinoce- 
ros. Sub-order  2. — Artiodactyla.  Ex.  :  Ox,  Pig,  Deer,  Cam- 
el, Anoplotherium,  Platygonus.  Order  7. — Amblypoda  (Cope). 
Ex. :  Dinoceras,  Uintatherium,  Loxolophodon.  Order  8. — Probo- 
SCIDEA.  Ex.  :  Elephas,  Mastodon.  ORDER  9. — Toxodontia. 
Ex. :  Toxodon,  Nesodon.  Order  10. — Tillodontia.  Ex.  :  Tillo- 
therium,  Anchippodus.     Order  1 1. — Rodentia.     Ex.:  Rat,  Squir- 

1  In  arranging  this  group  it  has  been  necessary  to  introduce  several  divisions  com- 
prising recently  discovered  American  fossil  forms.  These  groups  are  largely  provi- 
sional, and  it  is  probable  that  further  study  will  cause  extensive  changes  in  the  classifi- 
cation. The  outline  here  given  is  probably  as  satisfactory  as  is  possible  without  over- 
turning old  systems.  Cope  brings  together  into  new  Orders,  through  intervening 
fossil  forms,  members  of  groups  here  widely  separated. 


PALAEONTOLOGY.  53 

rel,  Hare,  Beaver,  Castoroides.  Order  12. — Carnivora.  Ex.  : 
Lion,  Tiger,  Bear,  Seal,  A/achairodus.  Order  13. — Insectivora. 
Ex.  ;  Mole,  Hedgehog,  etc.  Order  14. — Cheiroptera.  Ex.  :  Bat, 
Nyctilesles.     Order  15. — Primates.     Ex.  :  Lemur,  Ape,  Man. 

2.  Plants  best  Adapted  for  Fossilization.  a. 
Aquatics  and  marsh  plants  more  apt  to  meet  with  proper  con- 
ditions of  burial,  b.  Lowest  orders,  as  Algae  and  Lichens,  ap- 
proach most  closely  to  mineral  kingdom,  hence  most  readily 
produce  rocks,  c.  Nullipores  and  Corallines  secrete  CaO, 
hence  well  preserved. 

3.  Animals  and  Animal  Tissues  most  Permanent, 
a.  Soft  parts,  as  impressions,  or  as  interstitial  tissue  or  even 
(rarely)  as  adipocere,  occasional,  b.  Mineral  oil  or  coal  some- 
times left  by  decomposition  of  membranes  and  other  soft  por- 
tions, c.  Bones,  scales  and  hard  parts  generally,  preserved 
mainly  in  proportion  to  amount  of  earthy  matter;  hence  teeth 
more  commonly,  d.  Insects,  birds,  reptiles,  etc.,  living  in  or 
near  water  or  marshes ;  hence  Neuropiera,  Natatores,  Grallat- 
ores,  Amphibians,  etc.,  more  common  as  fossils,  e.  Inverte- 
brates more  common,  owing  to  small  proportion  of  animal  tis- 
sues in  exoskeletons.  f.  Vertebrates  less  common,  owing  to 
large  amount  of  animal  tissue  in  hard  parts. 

4.  Biological  Causes  of  Extinction  of  Types,  a. 
Species  inhabiting  shallow  water  more  liable  to  extermination 
by  changes  of  level,  b.  Terrestrial  forms  more  liable  to  suffer 
from  climatal  changes,  c.  Forms  most  removed  from  domi- 
nant type  succumb  in  "struggle  for  existence,"  if  antagonistic 
or  beneficial  to  " fittest." 

Ref. :— 1  (pp.  113-135,  etc.),  10,  114,  115,  116, 
117,  125. 

DIVISION  B.-OEOLOGICAL  RELATIONS. 

i.  Extinction  by  Geological  Agents,  a.  Changes  of 
level  of  land  (shore-travel),  producing  changes  in:  (1)  depth 
of  water  ;  (2)  amount  and  character  of  deposition  ;  (3)  temper- 
ature of  water;  (4)  land  climate,  b.  Approach  or  recession 
of  glaciers,  causing  climatal  changes,  etc. 

2.  Life-record  in  the  Rocks,  a.  Importance  of  "cycles 
of  deposition"  as  affecting  interpretation  [see  Ramsay's  ad- 
dresses (R.  65,  vols,  xix,  xx),  and  Hull  on  "Ternary  Classifica- 
tion" (R.  122,  1870)].     b.  Method  of  reading  record : 

(1)  Not  vertically  through  rocks,  but  in  zig-zag  manner,  following  move- 
ments of  shore-line. 


54 


GENERAL  GEOLOGY. 


(2)  Generally  speaking,  lineal  descendants  of  given  types  should  be  sought 
in  similar  strata  0/ succeeding  cycles  rather  than  in  superimposed  layers. 

(3)  il  Line  of  descent"  most  continuous  and  nearest  vertical  (stratigraph- 
ically)  in  strata  of  most  uniform  composition,  i.  e.,  in  cycles  of  greatest  du- 
ration. 

c.  Chronological  gaps,  caused  by  complete  denudation  of 
strata  or  by  absence  of  fossils  in  certain  rocks,  d.  Value  of 
negative  evidence  in  Palaeontology,  e.  Relation  of  Palaeon- 
tology to  hypothesis  of  "  Natural  Selection." 

Ref. :— 1  (pp.  763,  764),  2  (pp.  484,  485,  492, 
495-5°8)- 


PART  VI.-HISTORICAL  GEOLOGY  (STRA- 
TIGRAPHY). 

1.  Scope,  etc.  a.  Includes  history  of  earth  from  its  ori- 
gin to  beginning  of  human  records,  b.  Treats  of  physiographic 
and  geognostic  results  and  dynamical  action,  with  examination 
of  life-record,  of  successive  epochs  in  the  past. 

2.  Divisions.  A.  Nomenclature.  I.  Era.  a.  Broad- 
est division  of  geological  time.  b.  Based  upon  prominent 
characteristics  of  life.  II.  Age.  a.  Sub-division  of  Era.  b. 
Characterized  by  dominant  group  of  animals  or  plants,  III. 
Period,  a.  Sub-division  of  Age.  b.  Represents  history  of 
one  "cycle  of  deposition"  (in  effect,  not  always).  IV.  Epoch. 
a.  Sub-division  of  Period,     b.  Not  uniformly  defined. 

DIVISION  A.-GENEBAL  CONSIDERATIONS. 

i.  Value  of  Historical  Divisions,  a.  No  well  marked 
lines  of  separation,  b.  Strata  at  present  classified  somewhat 
arbitrarily,  c.  System  convenient,  but  complicated  and  more 
or  less  illogical,  d.  Best  divisions  those  in  which  strata  and 
fossils  lead  to  same  conclusions,  and  those  which  also  are  syn- 
chronous with  distant  beds.  e.  Distinction  between  synchron- 
ism and  "  ho?notaxis"  [Huxley,  R.  65,  vol.  xviii,  p.  xlvi],  or 
parachronism  [R.  55.  p.  143]. 

2.  Tests  of  Age  of  Strata,  a.  By  order  of  succession 
in  conformable  layers,    b.  By  structure  in  unconformable  beds. 


HISTORICAL  GEOLOGY.  55 

c.  By  means  of  fossils,     d.  Limited  value  of  color  and  litho- 
logical  character  as  comparative  tests. 

3.  Basins  of  Independent  Progress,  a.  Outlined 
almost  by  earliest  depressions  and  elevations  of  crust,  b. 
Boundaries  of  N.  American  areas : 

(1)  Eastern  Border.  Includes  whole  of  region  E.  and  N.  E.  of  Green 
Mts. 

(2)  Appalachian.  From  Quebec,  through  Green  Mts.,  S.  along  Appa- 
lachian Chain. 

(3)  Interior  Continental.  Between  Appalachians  and  Rocky  Mts.,  oc- 
cupying greater  portion  of  Mississippi  Valley. 

(4)  Cordillera.  Region  W.  of  Missouri  River  to  near  base  of  Pacific 
slope. 

(5)  Western  Border.     Portions  of  California,  etc.  W.  of  coast  ranges. 

(6)  Arctic  Border.     Not  clearly  defined. 

4.  Subdivisions  in  Geological  History,  a.  Each 
group  is  named  from  region  of  earth  where  its  rocks  are  best 
developed  or  from  character  of  most  abundant  fossils,  b. 
General  classification  of  sedimentary  strata,  beginning  with 
earliest. 

I— ARCHAEAN  ERA. 

AGE  A.— AZOIC  (Lifeless).  Period  1.  Nebular.  Period  £. 
Crustific 

AGE  B.— EOZOIC  (Life-dawn).  Period  1.  Phytogenic.  Pe- 
riod 2.  Laurentian.  Periods.  Huronian.  Period  4. 
Keewenawian  (T.  B.  Brooks). 

II.— PALAEOZOIC  ERA. 

AGE  C— LOWER  SILURIAN  (Brachiopods  and  Trilobites).  Pe- 
riod 1.  Cambrian.  EPOCH  I.  Acadian.  EPOCH  II.  Pots- 
dam.   Period  2.  Canadian.    EPOCH  I.  Calciferous.    EPOCH 

II.  Quebec.  EPOCH  III.  Chazy.  Period  3.  Trenton. 
EPOCH  I.  Trenton.  EPOCH  II.  Utica.  EPOCH  III.  Cin- 
cinnati. 

AGE  D.— UPPER  SILURIAN  (Invertebrates).  Period  1.  Ni- 
agara.     EPOCH  I.   Medina.      EPOCH  II.   Clinton.      EPOCH 

III.  Niagara.    Period  2.  Salina.    Period  3.  Helderberg. 

Transitional  Period.  Oriskany. 
AGE    E.— DEVONIAN    (Fishes).      Period    1.    Corniferous. 

EPOCH  I.    Cauda-galli.     EPOCH  II.   Schoharie.     EPOCH  III. 

Corniferous.      Period  2.   Hamilton.      EPOCH  I.  Marcellus. 

EPOCH   II.    Hamilton.     EPOCH    III.     Genesee.     Period   3. 

Chemung.     EPOCH  I.   Portage.     EPOCH  II.    Chemung.     Pe- 
riod 4.  Catskill. 
AGE  F.— CARBONIFEROUS  (Amphibians,  Acrogens).     Period 

1,  Sub-carboniferous.     EPOCH  I.  Lower  S.  C.     EPOCH  II. 

Upper  S.  C.      Period  2.  Carboniferous.     EPOCH  I.   Carb. 

Conglomerate  (Millstone  Grit).     EPOCH  II.  Lower  Coal  Measures. 

EPOCH  III.   Upper  Coal  Measures.     Period  3.  Permian. 


56  GENERAL  GEOLOGY. 

III.-MESOZOIC  ERA. 

AGE  G.— REPTILIAN.  Period  1.  Triassic.  EPOCH  I. 
Bunter-sandstein  {gres  bigarre).  EPOCH  II.  Muschelkalk  {Cal- 
caire  coquillier).  EPOCH  III.  Kenper  {Marne  irisee).  Period 
£.  Jurassic.  EPOCH  I.  Lias.  EPOCH  II.  lower  {Bath) 
Oolite.  EPOCH  III.  Middle  {Oxford)  Oolite.  EPOCH  IV.  Up- 
per {Portland)  Oolite.  EPOCH  V.  Wealden.  Period  3.  Cre- 
taceous. EPOCH  I.  Lower  Cret.  EPOCH  II.  Middle  Cret. 
EPOCH  III.  Upper  Cret.  (In  N.  A.— I.  Earlier.  II.  Later.) 
Traiisitional(!)  Period.  Lignitic. 

IV.-CMNOZOIC  ERA. 

AGE  H.— TERTIARY  (Mammals).  Period  1,  Eocene.  Pe- 
riod 2.  Miocene.     Period  3.  Pliocene. 

AGE  I.— QUATERNARY  (Man).  Period  1.  Glacial  (Drift). 
Period  2.  Champlain.  EPOCH  I.  Dihivian.  EPOCH  II. 
Alluvian  {Loess).  Period  3.  Recent.  EPOCH  I.  Reindeer. 
EPOCH  II.  Modern.     EPOCH  III.  Historical. 

Ref. : — i  (pp.4-6,  101-107,  136-146),  2  (chaps, 
xxvii,  xxviii,  xxix),  3  (pp.  266-271),  47,  116, 
117,  123  (tome  1,  Introd.) 

DIVISION  B.-AKCH^AN  ERA. 

A.— AZOIC  AGE. 

1.  Nebular  Period,  a.  Hypothetical,  based  on  nebular 
hypothesis,  b.  From  evolution  of  earth  from  sun  until  con- 
densation of  vaporous  mass. 

2.  Crustific  Period,  a.  Globe  cooling  at  centre  and 
finally  forming  crust  at  surface,  b.  Temperature  of  earth  not 
reduced  below  2000  F.  c.  Geosynclinals  formed  but  proba- 
bly of  little  permanence. 

2.  General  Remarks  on  Azoic,  a.  Rocks  not  certain- 
ly known. 

B.—EOZOIC  AGE. 

1.  Phytogenic  Period,  a.  Reduction  of  temperature 
sufficient  to  admit  of  growth  of  lowest  Cryptogamia  (not  above 
2000  F.)  b.  Thickening  of  crust,  formation  of  geosynclinals 
and  geanticlinals.  c.  Probably  small  areas  of  dry  land  before 
close,     d.   No  rocks  certainly  known. 

2.  Laurentian  Period.  a.  Distribution :  V-shaped 
area,  apex  N.  of  Great  Lakes,  running  N.  E.  to  Labrador, 
N.  W.  to  Arctic;  in  Appalachians,  Rocky  Mts.,  etc.,  etc.  b. 
Character  of  rocks  (not  always  readily  separated  from  Huro- 
nian)  : 


HISTORICAL  GEOLOGY.  57 

30,000  ft.  of:  (1)  granyte,  gneiss  and  mica  schist;  (2)  syenyte,  etc.; 
(3)  crystalline  limestone  ;  (4)  quartzyte,  etc.  ;  (5)  labradorite  ;  (6)  chrys- 
olite (common);   (7)  iron  ores,  except  limonite  ;   (8)  graphite,  etc. 

c.  Arrangement  and  structural  features,  d.  Original  condi- 
tion of  beds,  sedimentary,  e.  Alterations  and  disturbances. 
f.  Life: 

(1)  Plants  indicated  by  graphite  and  ores  of  iron  ;  (2)  Eozoon  Canadense 
and  allies  ;  (3)  Archmospherince ;  (4)  Palczohvchis  (doubtful);  (5)  An- 
nelids perhaps  indicated  by  tubes,  etc. 

3.  Huronian  Period,  a.  N.  of  L.  Huron,  S.  of  L. 
Sup'r(?),  N.  of  L.  Sup'r  and  N.  W. ;  elsewhere  doubtful,  b. 
Nature  of  rocks : 

15,000  ft.  to  20,000  ft.  of:  (1)  slates,  limestones  and  conglomerates; 
(2)  metamorphics,  etc.,  as  chert,  jasper,  dioryte,  chlorite  schist,  etc. 

c.  Paucity  of  fossils,  d.  Carbon  abundant,  e.  A.  A. 
Julien  reports  indistinct  Fucoidal  (?)  markings  [R.   124,  vol. 

H.P-S]- 

4.  Keewenawian   Period. (?)     a.   Name  suggested  by 

Major  Brooks  for  copper-bearing  series  of  L.  Superior. 

5.  General  Remarks  on  Eozoic  Age.  a.  In  Europe: 
N.  W.  Scotland,  Bavaria,  Bohemia,  Norway,  Sweden,  Finland, 
features  identical  with  N.  A.  rocks,  b.  Basins  outlined  in 
earliest  ages.  c.  General  character  of  earliest  life ;  supposi- 
tions as  to  forms  not  yet  recognized  as  fossils,  d.  Discussion 
concerning  nature  of  Eozoon. 

C.—CONCL  USIONS. 

i.  Length  of  Archaean  Time.  a.  Azoic  age  alone 
probably  at  least  of  as  great  duration  as  all  succeeding  time. 
b.   Calculations : 

(1)  Sir  Wm.  Thompson  estimates,  from  loss  of  heat  of  globe,  that  crust 
must  have  been  formed  at  least  20,000,000  yrs.  ago,  and  not  more  than 
400,000,000  yrs.  ago.      More  lately  he  gives  100,000,000  yrs.  [R.  2,  p. 

325]- 

(2)  Helmholtz,  from  cooling  of  lavas,  estimates  time  required  for  earth 
to  pass  from  2000°  C.  to  2000  C.  at  350,000,000  yrs.  [R.  I,  p.  147]. 

(3)  Temperature  at  close  of  Archaean  probably  not  above  400  C.  ;  hence 
at  least  30,000,000  yrs.  to  50,000,000  yrs.  more  necessary,  and  tempera- 
ture at  beginning  probably  much  above  20000  C. 

2.  Relations  of  Archaean  Basins  to  N.  American 
Continent,  a.  "V"  follows  two  main  systems  of  trends. 
b.  Other  regions  exposed  near  axes  of  prominent  ranges. 

Ref. :— 1   (pp.   146-161),   2    (pp.  523-525),  3 
(pp.  272-276),  10,  37,  116,  117. 


58  GENERAL  GEOLOGY. 

DIVISION  C.-PAt^OZOIC  ERA. 

A.— LOWER  SILURIAN  AGE. 

1.  Cambrian  Period.  A.  North  America,  a.  Flank- 
ing Archaean  ranges  and  in  some  distant  spots  in  interior,  b. 
Sandstones,  shales,  etc. ;  limestones  more  local ;  some  meta- 
morphics.  I.  Acadian  Epoch,  a.  S.  New  Br.,  at  St.  John  ;  S.E. 
Newfoundland,  b.  Shales  and  slates.  II.  Potsdam  Epoch. 
a.  Labrador  and  Newfoundland,  Vt. ;  Appal,  region  (3000  ft.), 
S.  to  Va.  and  E.  Tenn. ;  Int.  Cont.,  from  St.  Lawrence  Co., 
N.  Y.,  to  Can.,  S.  shore  of  L.  Sup'r  ("  Pictured"  and  "  Pillared" 
rocks)  into  Wis.,  Minn,  and  Iowa;  borings  show  it  in  Ohio, 
Ky.,  etc.;  Texas;  Rocky  Mts.,  base  of  Black  Hills,  Dak.,  Big 
Horn,  Wind  River,  Wahsatch,  Teton  and  other  ranges,  b. 
Red  and  whitish  sandstone,  shales  and  some  limestone ;  from 
60  ft.  (N.  Y.)  to  5000  ft.  (Appal,  region),  c.  Markings,  indi- 
cations of  near  coast  origin.     B.  Life.     a.  All  marine : 

(1)  PLANTS:   Fucoids. 

(2)  ANIMALS:  Protozoa — Rhizopods  indicated  by  "green  sand," 
Wis.  and  Tenn.  Ccelenterata — Hydrozoans,  Dendogroptus  Hallianus. 
Annuloida — Crinoid  stems,  Minn.  Mollusca — Brachiopods,  Lingn- 
lella  antiqua,  Lingnlepis  prinuzforviis,  Discina  acadica,  Orthis  Billingsii  ; 
Pteropods,  Hyalites  gregarius  ;  Gasteropods,  4  or  5  forms  ;  Cephalopods, 
2  sp.  of  Orthoceras,  Can.  Annui.OSA — Crustaceans — Trilobites,  Paradox- 
ides  (several  sp.),  Agnostus,  Conocoryphe. 

C.  Foreign  Cambrian,  a.  Wales  and  eastward.  I.  Har- 
lech  grits  and  Longmynd  slates.  II.  Meneviati  Group  (Acadi- 
an). III.  Lingula flags  (nearly  Potsdam),  b.  Lapland,  Nor- 
way, Sweden,  Bavaria,  Bohemia;  schists,  conglom.,  etc.  c. 
Life  very  similar  to  American,  but,  as  yet,  more  varied.  D. 
General  Remarks,  a.  Shallow  seas.  b.  Climate  uniform 
over  globe;  eyes  of  Trilobites  indicate  sunlight,  c.  Disturb- 
ances at  close  of  Acadian  in  Newfoundland,  possibly  at  close 
of  Potsdam  in  Idaho  and  eastward,  d.  Extinctions  of  species 
among  Trilobites. 

2.  Canadian  Period.  A.  N.  America.  I.  Calciferous 
Epoch,  a.  N.  N.  Y.  and  Can.,  S.  W.  Newfoundland  (2000  ft. 
of  Up.  Calcif.,  above  N.  Y.  Calcif.);  Appal.,  "Lower  Magne- 
sian  Limestone"  of  Mo.,  Iowa,  Wis.,  and  Upper  Mississippi 
Valley,  b.  Calcareous  sandstone  to  dolomite;  geodes  of 
quartz  (Middleville,  N.  Y.,  etc.)  II.  Quebec  Epoch,  a.  E. 
Can.,  S.  along  W.  base  of  Green  Mts.,  N.  W.  Newfoundland; 
E.  of  Hudson  R.  (Poughkeepsie),  Tenn. ;  Rocky  Mts.,  north- 
ward, b.  1500  ft.  to  6500  ft.,  sandstone  and  shales,  limestone 
westward.      III.    Chazy  Epoch,      a.  Range  same  as  Calcif., 


HISTORICAL  GEOLOGY.  59 

often  not  readily  separated ;  also  in  Arctic,  b.  Less  than 
1000  ft. ;  limestone,  magnesian  southward  and  in  Arctic.  B. 
Life.  a.  Fucoids,  Rhizopods,  Sponges,  Graptolites,  few  Ac- 
tinozoans,  Mollusca  (of  all  groups),  Worms  and  many  Trilo- 
bites.  C.  Foreign  Canadian,  a.  Difficult  "homotaxis." 
b.  Agrees  best  with  lower  part  of  foreign  Lower  Silurian. 
D.  General  Remarks,  a.  Deep  seas  in  Int.  Co///.,  shal- 
lower northward,     b.  Alternations  bet.  deep  and  shallow  seas. 

3.  Trenton  Period.  A.  N.  America,  a.  E.  of  Green 
Mts. ;  Appal.,  Trenton  Falls,  N.  Y.  and  southward;  O.,  Ind., 
111.,  Wis.  ("Galena  Limestone"),  etc.;  Arctic,  b.  Mainly 
limestone,  from  100  ft.  to  2000  ft.  I.  Trenton  Epoch  (Bird's- 
eye,  Black  River  and  Trenton  groups).  II.  Utica  (shale) 
Epoch.  III.  Cincinnati  Epoch  (Hudson  River  and  Cincinnati 
groups),  a.  Mt.  Washington,  etc. ;  S.  W.  Ohio,  through  Ky. 
into  Tenn.  (Nashville),  b.  Slates,  shales,  etc.  B.  Life.  a. 
Same  group  as  before,  with  addition  of  many  Corals,  Crinoids, 
Cystids,  Mollusca  (all  fossil  groups,  but  Brachiopods  still 
most  abundant) ;  Trilobites  very  common.  C.  Foreign,  a. 
Brit.  Is.,  Bohemia,  Scandinavia,  etc.  b.  Lower  part  of  Ca?-a- 
doc  atid  Bala  Group.  D.  General  Remarks,  a.  Forma- 
tion of  limestones  over  wide  area  in  Int.  Cont.  indicates  pres- 
ence of  barrier  along  E.  Bo)'d.  during  Trenton  Epoch,  b.  Part 
of  barrier  submerged  during  Cinn.  Epoch,  while  waters  became 
shallower  in  Int.  Cont.  c.  Cumberland  sandst.  in  Ky.  repre- 
sents gradual  transition  to  Up.  Silurian. 

4.  Review  of  Lower  Silurian,  a.  Appal.,  thickest  de- 
posits; shallow  water  beds;  greatest  changes  of  level,  b. 
Ocean  climate  not  diversified,  c.  Probable  absence  of  very 
high  land.  d.  Land  area  limited,  if  absence  of  terrestrial  fos- 
sils be  criterion. 

5.  Disturbances  at  Close  of  Lower  Silurian,  a. 
Green  Mts. ;  extensive  geosynclinal,  with  faults  in  positions  of 
eroded  anticlinals  of  the  synclinorium.  b.  Cincinnati  geanti- 
clinal,  less  marked  and  less  ruptured,  c.  Beds  of  succeeding 
AGE  overlie  these  unconformably  in  Europe;  disturbances 
not  general. 

B.—  UPPER  SILURIAN  AGE. 

i.  Niagara  Period.  A.  North  America.  I.  Medina 
Epoch  (Oneida  congl.,  Medina  sandstone),  a.  N.  Y.,  Upper 
Can.,  W.  Mich,  Penn.  and  Tenn.  b.  About  400  ft.  to  2000 
ft.,  congl.  and  sandstone.  II.  Clinton  Epoch,  a.  N.  Y., 
through  Can.  to  Mich.,  Wis.,  Ind.,  Ohio,  Penn.,  Va.,  Tenn. 


60  GENERAL  GEOLOGY. 

b.  Shales,  sandstone,  limestone,  iron  ore  {hematite).  III.  Ni- 
agara Epoch,  a.  Anticosti,  Brit.  Amer.,  Arctic,  N.  Y. ;  Rocky 
Mts.,  far  west  and  south,  b.  Mainly  limestones,  300  ft.  to 
1500  ft.  B.  Life.  a.  Medina  and.  Clinton:  Fucoids ;  Sponges, 
Corals  {Favosites,  Halysites  etc.),  Crinoids  (star-Jish),  Brachio- 
pods,  Lamellibranchs.  b.  Clinton  and  Niagara  limestones: 
Corals,  Crinoids,  few  Lamellibranchs,  Trilobites.  C.  Foreign. 
a.  Similar  in  features,  b.  Limestones  less  abundant  in  Gt. 
Britain.  D.  General  Remarks,  a.  Shore-line  moving  west- 
ward, elevating  E.  N.  Y.  in  earlier  epochs,  finally  deepening 
waters  in  interior,  b.  E.  Bord.  somewhat  independent  in 
progress. 

2.  Salina  Period  [Onondaga  Salt  Group).  A.  N.  Amer- 
ica, a.  N.  N.  Y.,  (S.  of  Erie  Canal),  bet.  Niagara  River  and 
L.  Huron,  Mich.,  W.  Ohio,  S.  W.  Va.  b.  700  ft.  to  1000  ft. 
in  N.  Y.,  shales  and  marly  beds,  with  salt  (Syracuse).  B.  Life. 
Rare.     C.  *  *  *  * .     D.  General  Remarks,    a.  Interior 


a. 


shallow  sea,  with  sand  flats  and  marshes,     b.  Thickness  of 
beds  indicates  subsidence. 

3.  Helderberg  Period.  A.  N.  America,  a.  N.  Y., 
Penn.,  Md.,  Va.,  Ohio,  S.  111.;  E.  Border,  b.  350  ft.  to  2000 
ft.,  limestone  {Lower  Water-lime  Group).  B.  Life.  a. 
Abundant ;  300  sp.,  same  Fam.  and  Gen.  as  before,  but  new 
species,  b.  Corals,  Crinoids,  Cystids,  Worms,  new  Crustaceans 
{Eurypterus,  Bterygotus,  Ceratiocaris),  Trilobites,  Ostracoids, 
etc. 

4.  Foreign  Upper  Silurian,  a.  Less  wide  spread  than 
L.  Sil.,  but  extensive;  Europe  (except  Spain  and  France), 
Asia,  Africa,  Australia,  Brazil,  b.  Terrestrial  life:  (1)  Plants 
— Lepidodendron,  Brototaxites,  Bachytheca,  etc.;  (2)  Animals — 
Invert,  similar  to  American;  First  Vert.  {Fishes),  Bteraspis, 
Cephalaspis,  Coccosleus,  Bterichthys,  Elasmobranchs. 

5.  Review  of  Upper  Silurian,  a.  E.  Bord.  still  more 
distinct,  even  in  character  of  Life.  b.  Land  mainly  submerged, 
except  at  north,  c.  Seas  warm  and  rather  uniform,  d.  Ex- 
tinctions:  (1)  Graptolites ;  (2)  several  genera  of  Trilobites. 
e.  Special  features  of  life:  (1)  Spirifers  broader  winged  than 
before;  (2)  Lamellibranchs  and  Gasteropods  chiefly  of  siphon- 
less  divisions. 

Oriskany  (Transitional)  Period. 
A.  N.  America,     a.  Narrow  belts  in  N.  Sc,  through  Me. 
and  Vt.,  southwestward ;  Oneida  Co.,  N.  Y.,  S.  W.  along  Appal., 
W.  through  Can.,  Ohio,  Ind.,  111.  and  Mo.     b.  Limestone,  E. 


HISTORICAL  GEOLOGY.  61 

Bord. ;  sandstone,  N.  Y.,  with  some  limestone  westward.  B. 
Life.  a.  Algae;  Lycopods  (Psilophyton princeps  Dawson)  in 
Can. ;  Crinoids :  Spirifer  arenosus,  Rensselaeria  ovoides  and 
other  Brachiopods ;  Lamellibr.,  Gasteropods  and  Ceph.  C. 
Foreign,  a.  In  Europe,  "Tilestones"  are  beds  of  passage 
bet.  U.  Sil.,  and  Devonian ;  elsewhere  transition  also  gradual. 
D.  General  Remarks,  a.  Probably  interior  seas  opening 
southeastward,  Green  Mts.  and  Archaean  Highlands  being  out 
of  water,  b.  Elevation  in  E.  N.  Y.  of  land  previously  sub- 
merged, c.  Allied  to  U.  Sil.  by  character  of  life,  by  structure 
of  rocks,  etc.,  to 

C— DEVONIAN  AGE. 

i.  Corniferous  Period.  A.  N.  America.  I.  Cauda- 
galli  Epoch,  and  II.  Schoharie  Epoch,  a.  Both  in  Appal.,  E. 
half  of  N.  Y.  b.  Grits.  III.  Corniferous  Epoch,  a.  Vt. 
and  Mass.,  Can.  and  westward,  southward  in  Ky.,  etc.  b. 
Limestone  (Onondaga  and  Corniferous),  50  ft.  to  300  ft,  with 
chert.  B.  Life.  a.  Desmids,  Diatoms,  Algae  (Spirophyton 
cauda-galli),  Lycopods,  Ferns,  Tree-ferns  (Ohio),  Conifers  (Pro- 
totaxites)  :  Sponges,  Cyathophylloid  corals  and  others  (Eavo- 
sites,  etc.),  forming  reefs,  as  at  Falls  of  Ohio,  Louisville;  Blast- 
oids  (Nucleocrinus),  Brachiopods  [first  Productd),  Gasteropods, 
Pteropods  (Tentaculites  scalaris),  Cephal.  (Orthoceras,  Cyrtoce- 
ras,  etc.),  Trilobites ;  Fishes  (first  Vert,  in  Amer.),  Elasmobr. 
and  Ganoids,  representing  all  subdivisions  given  in  foot  note l 
[R.  128,  Palaeont.,  vol.  i,  pp.  264-268].  Ex. :  Holocephali — 
Rhynchodus  [R.  128,  loc.  cit.,  PI.  28,  29];  Plagiostomi — Psam- 
modus  (Cestraciont),  Machaeracanthus  and  Cyrtacanthus  (Hybo- 
dont) ;  Placoganoidei — Acanthaspis,  Cephalaspis,  Macropetal- 
ichthys;  Lepidoganoidei — Onychodus.  C.  Foreign,  a. 
Lower  Dev.  and  part  of  Middle  Dev.  of  Europe.  D.  Gen- 
eral Remarks.  a.  Climate  not  greatly  diversified  over 
globe.  b.  Considerable  increase  of  land.  c.  Deep  sub- 
mergence of  E.  N.  Y.  during  Corniferous  Epoch,  as  shown  by 
hornstone  and  corals,  d.  Some  reason  for  belief  that  this  form- 
ation occurs  in  Arctic  [R.  13,  II,  xxvi,  120]. 

1  See  ante,  p.  51,  (VI,  Prov.  A,  CI.  I).  Order  2. — Elasmobranchii.  Sub-order  i. 
— Holocephali  (Genus  Chim&ra).  Mouth  at  end  of  head ;  single  external  gill  slit, 
operculated.  Sub-order  2. — Plagiostomi.  Mouth  transverse  on  under  side  of  head; 
several  non-operculated  gill  slits  on  each  side  of  neck.  Family  a.  Cestracionts.  Mas- 
ticatory apparatus — bony  pavement.  Ex.  :  Port  Jackson  (Australia)  .--hark,  Acrodus. 
family  b.  Selachians.  Hybodont  or  Squalodont  dentition,  "placoid"  scales.  Ex.: 
Sharks.  Order  4. — Ganoidei.  Sub-order  i. — Placoganoidei  (Placodermi).  Part- 
ly or  wholly  covered  by  polygonal  ganoid  plates.  Ex.  :  Pteraspis,  Pterichthys, 
Cephalaspis.  Sub-order  2. — Lepidoganoidei.  Ganoid  scales  like  living  forms.  Ex.: 
Amia,  Lepidosteus,  Hoicptychius,  etc. 


62  GENERAL  GEOLOGY. 

i.  Hamilton  Period.  A.  N.  America.  I.  Marcellus 
Epoch;  II.  Hamilton  Epoch;  III.  Genesee  Epoch.  a.  E. 
fiord.,  similar  to  Cornif.  ;  Hudson  River,  through  Cent.  N.  Y., 
across  L.  Erie  into  S.  Mich.,  W.  Penn.,  E.  Ky.,  etc.,  O.,  Iowa, 
S.  W.  Minn.,  E.  Dakota,  northward,  b.  Mainly  shales,  with 
sandstone  in  E.  fiord,  c.  Ripple-marks,  septaria,  etc.,  as  on 
Cayuga  Lake,  N.  Y.  d.  Joints,  etc.  B.  Life.  a.  Lycopods 
(Psilophyta,  Lepidodcndron,  Sigillaria,  Stigmaria),  Ferns,  Equi- 
setaceae  (Catamites,  Asterophyllites),  Charoz ;  Gymnosperms 
(Coniferce)1 ;  Brachiopods  abundant,  Lamell.,  Gaster.,  Cephal. 
(first  Goniatites);  Trilobites.  First  Insects,  May-Fly ;  Fishes 
(Dinkhthys,  Paltzonisciis,  Cephalaspis).  C.  Foreign,  a.  Up- 
per part  of  Middle  Dev.  D.  General  Remarks,  a.  Shallow 
water  E.,  deeper  W.  b.  Genesee  quite  wide  spread,  indicating 
shallow  sea  in  Int.  Cont.  c.  Land  frequently  exposed,  as 
shown  by  terrestrial  plants  and  insects,  marsh  dwellers. 

3.  Chemung  Period.  A.  N.  America.  I.  Portage 
Epoch;  II.  Chemung  Epoch,  a.  E.  fiord.,  same  as  Hamil- 
ton;  Hudson  River,  S.  W.  along  Appal.,  through  N.  Y.,  W. 
Pa.,  Cent.  Ohio,  along  shores  of  L.  Erie.  b.  Less  than  3500 
ft.,  shallow  water  beds,  sandstone  and  shales.  B.  Life.  a. 
Plants  as  before,  b.  Animals  characteristic,  but  similar  to 
Cornif.  c.  Local  features  about  Ithaca.  C.  Foreign.  #  #  # 
D.  General  Remarks,  a.  Continuation  of  previous  condi- 
tions northward,  b.  In  Ky.  and  other  parts  of  Int.  Cont., 
wholly  absent,2  indicating  elevation  of  land  out  of  water. 

4.  Catskill  Period.  A.  N.  America,  a.  N.  N.  Y., 
Penn.,  Appal. ;  E.  fiord,  as  in  previous  periods,  b.  Reddish 
sandstones  and  shales,  5000  ft.  to  6000  ft.  B.  Life.  a.  Not 
very  abundant;  Plants,  Fishes,  etc.;  no  Corals,  Crinoids, 
Brachiopods  or  Trilobites.  C.  Foreign,  a.  Homotaxis  not 
apparent.  D.  General  Remarks,  a.  Eastward  movement 
of  shore-line,  followed  by  movement  southward. 

5.  Review  of  Devonian  Age.  A.  Geography,  a. 
Land-area  considerably  increased,  b.  Large  rivers  of  north  (as 
Hudson  and  Conn.)  probably  existing  towards  close  to  near 
present  extent,  c.  In  Europe  more  diversified  land  and  water 
areas.     B.  Life,  etc.     a.  Terrestrial  plants,  Insects,  Fishes 

1  For  descriptions  of  Dev.  Plants,  see  J.  W.  Dawson,  R.  37  (1871),  65  (xv,  483;  xviii, 
296;  xix,  458;  xxvii,  270);  Ch.  Fred  Hartt,  R.  127  (Bailey's  N.  B.  Reft,  1865). 

2  In  Ky.  a  thick  mass  of  "  Devonian  Black  Shale"  represents,  probably  Genesee 
Epoch,  but  may  be  synchronous  with  part  of  Chemung  Period  also.  Dr.  J.  S.  New- 
berry regards  parachronous  beds  in  Ohio  as  the  equivalent  of  both  Genesee  and  Portag* 
in  N.  Y. 


HISTORICAL  GEOLOGY.  63 

most  prominent,  b.  Broad-winged  Spirifers  ;  increase  in  size 
of  Proditcta.  c.  New  types  introduced,  as  (i)  Producta,  (2) 
Goniatites,  (3)  Nucleocrinus,  all  culminating  later  and  becoming 
extinct  in  Palaeozoic  Era.  d.  Extinctions :  (1)  Cystids1  (Oris- 
kany) ;  (2)  several  genera  of  Corals,  Crinoids,  Brachiopods. 
e.   Climate  but  little  changed  from  preceding  Ages. 

6.  Disturbances  at  Close  of  Devonian,  a.  E.  Bord.t 
extensive,  permanently  elevating  Maine;  less  marked  in  Conn. 
Valley  and  in  N.  Y.  State,  b.  N.  Europe,  but  not  below 
Cent.  France. 

J).— CARBONIFEROUS  AGE. 

i.  Sub-carboniferous  Period.  A.  N.  America.  I. 
Lower  S.  C.  Epoch  ;  II.  Upper  S.  C.  Epoch,  a.  N.  S.,  N.  B. ; 
Va.,  Ala. ;  Tenn.,  Ky.,  N.  E.  Miss.,  Mo.,  Iowa,  Ind.,  O.,  Mich., 
Wyo.  (??),  Mont.,  Idaho,  Wahsatch,  Humboldt  and  other 
ranges,  N.  Calif,     b.  Rocks: 

E.  Boni., — Lower,  sandstone,  congl.,  albertite,  coal,  etc.  {Horion) — 
Upper,  limestone  (fossil),  marls,  with  gypsum  { Windsor) — together  6000 
ft.;  Penn. — Lower  {Vespertine),  2000  ft.,  sandstone  and  congl. — Upper 
( Umbral),  3000  ft.  shales,  reddish ;  Ohio  ( Waverley),  sandstone,  thin 
beds  of  shale  and  limestone;  Tenn.,  1200  ft. — Lower,  siliceous — Upper, 
calcareous;  111.,  1500  ft.,  1  {Kinderhook,  250)  sandstone  and  shales,  2 
{Burlington,  200)  limestone,  3  {Keokuk,  250)  limestone  and  quartz  ge- 
odes,  4  {St.  Louis,  250)  limestone,  oolyte,  etc.,  5  {Chester,  600)  limestone. 
Ky.,  thick,  synchronism  doubtful;  Keokuk,  St.  Louis,  Chester  prominent ; 
Iowa,  500  ft.  (no  Chester). 

B.  Life.  a.  Plants  abundant,  genera  as  before,  b.  Increase 
of  Corals,  Echinoderms,  Polyzoans,  Lamellibr.,  Gasteropods, 
Ceph.,  Crustaceans,  Insects  and  Fishes,  c.  Culmination  of 
Crinoids,  Blastoids,  Spirifera,  Producta,  Goniatites,  etc.  d.  In- 
troduction of  beaked  Gasteropods,  2  new  genera  of  Trilobites, 
Amphibians.  C.  Foreign,  a.  Similar  to  American  in  Gt. 
Brit.,  Belgium,  Russia,  etc.  b.  Trap  ejections  in  Gt.  Brit., 
also  in  New  Br.  c.  Eusulina  (Rhizopod)  common  in  Europe, 
not  known  in  Amer.  Sub-carb.  I).  General  Remarks,  a. 
Limestone  forming  seas  in  all  regions,  b.  Overlap  (?)  in  111., 
Iowa  and  Mo.  c.  Unconformity  with  overlying  beds  in  Ba- 
varia and  in  S.  and  Cent.  France,  d.  Remarkable  parallelism 
in  life  throughout  the  world. 

2.  Carboniferous  Period.2  A.  N.  America.  I.  Car- 
boniferous Conglomerate  [Millslofie  Grit)  j  II.  Lower  Coal 
Measures ;    III.     Upper  Coal  Measures  {Carboniferous  Lime- 

1  One  now  living  in  depths  of  Atlantic  (Loven). 

*  This  Period  being  always  discussed  at  length  in  text-books,  it  is  here  less  fully 
outlined  than  its  importance  would  otherwise  necessitate. 


64  GENERAL  GEOLOGY. 

stone),  a.  S.  W.  Newfoundland,  N.  S.  and  N.  B.,  R.  I.,  Mass, 
S.  N.  Y.,  Penn.,  Va.,  VV.  Va.,  Ky.,  Tenn.,  Ala.;  Ohio,  Lower 
Penin.  of  Mich.,  Ind.,  111.,  Iowa,  Mo.,  E.  Miss.,  Texas,  Ark., 
Kansas,  Neb.;  Colo.,  Wyo.,  Mont.,  Nev.,  Utah,  Calif.;  Arctic. 
b.  9000  ft.  (Penn.)  to  14,500  ft.  (N.  S.) ;  I.  Congl.  and  sand- 
stone; II.  Sandstone,  congl.  and  coal  (from  papery  to  40  ft.) 
B.  Life.  a.  Plants  remarkably  abundant,  same  fades  as  De- 
vonian, b.  First  Cycads,  some  evidence  of  Fungi,  c.  Fusu- 
lina  •  Corals  and  Crinoids  diminish ;  Lamellibr.,  Brachiopods 
abundant,  land  Gasteropods;  few  Orthoccras,  Goniatites,  etc.; 
a  few  Worms  and  Trilobites;  Crustaceans — Decapoda  (Ma- 
crura)  and  Merostomata  ;  several  Orders  of  Insects ;  numer- 
ous ancient  Fishes,  Hypodont  Sharks  abundant ;  Amphibians, 
few  Reptiles.  C.  Foreign,  a.  Very  similar  to  American.  D. 
General  Remarks,  a.  Period  of  oscillation,  with  excess  of 
elevation  eastward,  of  deep  submergence  largely  in  far  west. 

b.  Marshes  for  growth  of  coal  plants,  c.  Coal  result  of  accu- 
mulation, decomposition  and  compression  of  vegetable  matter 
not  in  direct  contact  with  atmosphere,     d.  Note : 

It  is  impossible  to  treat  this  subject  as  it  deserves  within  the  limits  of 
this  work,  even  synoptically.  Students  should  roughly  note  during  the 
lecture  the  topics  which  seem  most  important,  afterward  directing  their  read- 
ing towards  the  general  principles  of  the  discussion,  without  devoting 
much  time  to  special  facts  and  conclusions,  which  will  be  taken  up  in  the 
course  of  lectures  on  Economic  Geology. 

e.  Temperature  of  water  over  globe  not  below  68°F.,  as 
Corals  of  this  Period  are  found  even  in  Arctic,  f.  Climate 
moist,  g.  Air  must  have  had  more  C02,  as  coal  now  repre- 
sents C  then  abstracted  by  plants. 

3.  Permian  Period.  A.  N.  America,  a.  Kansas  and 
E.  slope  of  Rocky  Mts.  b.  Less  than  1000  ft.  at  utmost,  lime- 
stones, shales,  marls,  sandstone.  B.  Life.  a.  Fossils  few, 
marine ;  Mollusca,  some  teeth  of  Fishes,  etc.  C.  Foreign. 
a.  Rocks  similar,  with  red  sandstone,  b.  Breccia  in  Lower 
Perm,  of  Engl.,  perhaps  indicates  iceberg  action   (Ramsay). 

c.  Life  rather  abundant;  plants  similar  to  Upper  C.  M. ;  ani- 
mals more  or  less  characteristic,  d.  Introduction  of  Theco- 
dont Reptiles  (Crocodilia,  with  affinities  to  Deinosauria), 
as  Proterosaurus.  e.  Extinctions:  (1)  among  Brachiopods, 
Ort/iis,  Producta  and  other  genera;  (2)  cyathophylloid  Corals 
(nearly);  (3)  heterocercal  Ganoids  (mainly).  D.  General 
Remarks,  a.  Movement  of  interior  sea  westward  by  previous, 
elevation  of  Mississippi  Valley,  b.  Similar  relation  in  Europe 
to  Volga  Riv.  and  Ural  Mts.     c.  Continuation  over  restricted 


HISTORICAL  GEOLOGY.  65 

area  of  Carboniferous  conditions,  d.  Transition  to  Mesozoic 
conditions. 

E.—COiVCL  USIONS. 

i.  Thickness  of  Palaeozoic  Strata,  a.  Maximum 
over  50,000  ft.;  L.  Sil.,  from  700  ft.  (111.)  to  15,000  ft.  (E. 
Tenn.) ;  Up.  Sil.,  90  ft.  (Mich.)  to  nearly  10,000  ft.  {Appal.) , 
Dev.,  130  ft.  (Mo.)  to  more  than  1400  ft.  {Appal.);  Carb., 
850  ft.  (Mich.)  to  14,570  ft.  (NVS.)  b.  In  Appal.,  45,000  ft. 
(sandstone,  shales,  etc.) ;  Int.  Cont.,  only  3000  ft.  to  6000  ft. 
(limestone  largely). 

2.  Estimate  of  Length  of  Palaeozoic  Time.  a. 
From  thickness  of  strata : 

(1)  Dana  (R.  i,  p.  381)  gives  ratio  of  L.  Sil.,  U.  Sil.,  Dev.,  Card. 
and  Potsdam,  respectively  ;  3.5  :  .62+  :  1  :  1 :  I. 

(2)  Allowing  extremely  rapid  rate  of  accumulation  (average  of  10  ft.  per 
century),  Potsdam  Epoch  alone  80,000  yrs.,  and  PALAEOZOIC  ERA 
about  590,000  yrs. 

3.  Life  of  Era.  a.  Review  of  general  progress,  b. 
"  Comprehensive  types."  c.  Palaeozoic  flora  and  fauna  char- 
acterized by  great  size.  d.  Animals  have  often  degraded 
features  of  colonization,  multiplicity  of  parts,  immobility,  e. 
Parallel  groups  co-existent.  f.  Palaeozoic  Molluscan  genera 
now  living,  as  Lingula,  Terebratula  (late  Pal.),  Ostrea,  etc. 

4.  Disturbances  at  Close,  a.  Elevation  of  Appalach- 
ians (except  previously  formed  Green  Mts.)  and  exposure  of 
land  over  area  E.  of  Mississippi  Riv.  b.  In  Europe  extensive 
disturbances,  partly  bet.  Carb.  and  Perm.  c.  Examples  of 
remarkable  faults,  as  in  Ky.  Tenn.  and  Va. 

Ref. :— 1  (pp.  162-402),  2  (pp.  520-610),  3  (pp. 
276-304),  9,  10,  47,  117,  127,  128,  129. 

DIVISION  D— MESOZOIC  ERA. 

A.— REPTILIAN  AGE. 

1.  Triassic  Period.  A.  N.  America,  a.  N.  S.„  Pr. 
Edw.  Is. ;  Conn.  Valley,  Palisade  belt,  (S.  E.  N.  Y.  to  Rich- 
mond, Va.)  and  Deep  River  (N.  C.) ;  Blk.  Hills,  Wahsatch, 
Uintah,  Wind  River  ranges,  etc.;  Calif.,  Alaska,  b.  3000  ft. 
to  5000  ft,  sandstone,  commonly  reddish,  with  gypsum  in 
northwest  (Wind  River  Valley).  B.  Life.  a.  Very  few  re- 
mains in  U.  S.  except  in  W.  Bord.  b.  Plants;  Tree-ferns, 
Cycads,  Conifers,  c.  Animals ;  mingling  of  Palaeozoic  forms 
{Spirt/era,  Orthoceras,  Goniatites)  with  Mesozoic  {Ceratites, 
5 


66  GENERAL  GEOLOGY. 

etc.) ;  Ostracoids,  Neuropters ;  Ganoids  [heterocercal,  homo- 
cereal  and  protocercal);  Labyrinthodonts,  Deinosaurs,  "bird 
[Deinosaur?]  tracks"  of  Conn.  Valley,  Crocodilia  (Theco- 
donts Belodon,  etc.) ;  Lacertilia  (Rhynchosaurus,  also  allied 
to  Chelonia);  Marsupial  (Insectivorous  (?)  Dromatherium). 
C.  Foreign.  (See  Epoehs  given  a?ite,  p.  56).  a.  Deposits,  Life, 
etc.,  remarkably  similar  to  American.  D.  General  Remarks. 
a.  Markings  in  beds,  showing  shallow-water  origin,  b.  Ameri- 
can in  rocks  and  life,  European  in  life,  rather  closely  related 
(though  transitional)  to  Jurassic,  c.  Disturbances;  eruption 
of  N.  J.  trap  ridges,  but  in  such  manner  as  to  show  previous 
tilting  of  sandstone.  d.  American  coast  line  farther  seaward 
than  now.  e.  Climate  less  uniform  than  before,  but  still  not 
much  differentiated. 

2.  Jurassic  Period.  A.  N.  America,  a.  Undefined, 
except  in  Rocky  Alts.  b.  Limestone,  etc.  B.  Life.  a.  New 
forms  of  animals,  as  Gryphcea,  Belemniies  (endo-skeleton,  Di- 
branchiata),  fragments  of  uncertain  Reptiles.  C.  Foreign. 
(See  ante,  p.  56,  for  division  into  Epochs),  a.  Life  similar  to 
Triassic,  with  additions;  Rhizopods  [Orbitolites,  Nummulites), 
Sponges,  Corals  (some  Zoantharia),  Crinoids  (some  free), 
characteristic  modern  Brachiopods  (old  forms  die  out,  as  Spirif- 
era,  etc.),  Terebratula,  Rhynchonella,  special  Lamellibr.,  Gas- 
teropods,  Ammonites  abundant,  Dibranch.  Ceph. ;  Annelids, 
Crustaceans,  Arachnids,  all  groups  of  Insects ;  Ganoids  (none 
heteroccrcal)  Elasmobr.,  (first  Squalodonts)  first  Teliosts;  Ich- 
thyosaurus, Plesiosaurus,  Pliosaurus,  Teleosawus,  Rhynchosau- 
rus,  Rhamphorhynchus ;  Crocodilia  (Cetiosaurus,  etc.,  first 
Crocodihis),  Deinosauria  (Megalosaurus,  Iguanodon,  etc.), 
Pterosauria  {Pteiydactylus,  etc.)  Chelonia;  Birds  [Archoz- 
opteryx);  Mammals  all  Marsupials,  niostly  Insectivorous,  but 
2  sp.  of  Plagiaulax,  allied  to  Kangaroo-rat  (Rodent-Marsup.), 
and  one  (Galastes)  Predaceous.  D.  General  Remarks,  a. 
Absence  of  strata  along  present  Amer.  coast  indicates  eastward 
extension  of  Jurassic  shore-line.  b.  Climate  somewhat  more 
differentiated  than  before,  but  still  temperate  even  in  Arctic,  c. 
Disturbances:  (1)  elevation  of  Sierra  Nevada  and  Wahsatch 
Mts.,  Uintah  Mts.  [see  R.  55  (pp.  99,  154),  130  (Geol.  vol.  i), 
131  (vol.  ii,  also  vol.  iii,  p.  4)]. 

3.  Cretaceous  Period.  A.  N.  America.  I.  Earlier 
Cretaceous  Epoch  (Dakota,  Benton,  Niobrara  groups);  II. 
Later  Cretaceous  Epoch  (Fort  Pierre,  Fox-Hills  groups),  a. 
N.  J.  (below  Sandy  Hook)  to  S.  C,  Gulf  States,  Miss.  Valley, 


i*£  fo^l 


■  ■  •  i . 


. 


-    ' 


HISTORICAL  GEOLOGY.  67 

Rocky  Mts.,  Coast  Ranges,  Brit.  Amer.,  Arctic,  etc.  b.  Max- 
imum over  10,000  ft.  (9000  ft.  in  Wyo.,  Utah  and  Col.),  sili- 
ceous and  calcareous.  B.  Life.  a.  Coccoliths,  first  Angio- 
sperms — Oak,  Poplar,  Maple,  Willow,  Beech,  Sassafras,  Syca- 
more, Liriodeudron.  b.  Foraminifera  (Orbitoliua,  Nummu- 
lites) ;  Terebratulids,  Ostreidae,  Rudistes  group  (aberrant  and 
characteristic,  not  found  later) ;  Belemnites,  numerous,  often 
very  large  Ammonites  (coiled,  partly  coiled  and  even  straight) ; 
Fishes  numerous, yf/'^/Teliosts  in  N.  America,  Selachians  (Squal- 
odonts,  last  of  Hybodonts)  more  abundant  than  Cestracionts. 
Deinosaurs  very  abundant,  Crocodilia,  first  Amer.  Che- 
lonia  {Trionyx,  Atlantochelys,  some  very  large  in  higher  beds), 
Plesiosauria  [Pliosaurus,  etc.,  not  Plesiosanrus  and  Ichthyo- 
saurus in  N.  Amer.),  Pterosauria  (large  forms,  wings  spread- 
ing 10  ft.  to  25  ft.);1  first  Amer.  Birds  (Odontomithes,  and 
other  extinct  forms,  largely  aquatic) ;  no  Mammals  yet  discov- 
ered (1878),  probably  some  living  in  Cretaceous,  however. 
C.  Foreign.  a.  Sandstone,  marls,  chalk,  "green-sand,"  etc. 
b.  S.  American  Cretaceous  (Prof.  Hartt's  discoveries),  c.  Life 
as  in  Amer.,  and  very  abundant,  d.  Besides  Amer.  Plants : 
Desmids,  Diatoms,  Palms,  and  some  characteristic  Phanero- 
gams, e.  Animals  special:  Chalk  Foraminifera,  Sponges; 
Ichthyosaurs  and  Plesiosaurs,  Pterydactyles.  D.  General 
Remarks,  a.  Extension  of  American  coast  line  southward. 
b.  Review  of  geography  during  Cret.  times;  Miss,  and  Ohio 
rivers  discharged  into  bay  near  present  mouth  of  latter,  Del- 
aware Riv.  reached  ocean  near  Trenton,  N.  J. ;  Missouri  hy- 
drographic  basin  mainly  submerged,  etc. ;  Andes,  Alps,  Hima- 
layas more  or  less  submerged,  etc.  c.  Climate  probably  more 
rigorous  than  before  in  polar  regions. 

4.  Disturbances  at  Close  of  Cretaceous,     a.  Eleva- 
tion of  Rocky  Mts.     b.  European  elevations. 

Lignitic  (Transitional  ?)  Period. 
A.  N.  America,  a.  Perhaps  at  Brandon,  Vt. ;  Tenn.,  Miss., 
Ark.;  Texas;  Fort  Union,  Judith  Basin;  Brit.  Amer.  b. 
Sandstone  and  clays,  with  lignite,  coal  and  even  anthracite.  B. 
Life.  a.  Plants:  200  sp.  of  forms  even  more  modern  than 
undoubted  Cretaceous,  b.  Animals  of  Cret.  types  :  Free  Crin- 
oids,  Ostrea  congesta,  Inocera??ius  problematicus,  Anomia  sp., 
Fishes  (Lepidotus,  etc.),  Deinosaurs,  Megalosaurs,   Crocodilus, 

1  These  forms,  of  genera  Pteranodon  and  Nyctosaiinis,  are  now  placed  in  a  distinct 
order  of  Reptiles,  known  as  Pteranodontia  (literally  winged-toothless) ,  by  Marsh. 


68  GENERAL  GEOLOGY. 

Chelonia  (Trionyx,  Emys,  etc.)  c.  Animals  upon  which  ref- 
erence to  Eocene  Tertiary  is  based  by  some  authorities  (Les- 
quereux,  etc.) :  mainly  Mollusca  of  brackish  water  and  fresh 
water  types,  d.  Ammonites  become  extinct,  also  Deinosaurs. 
e.  Note: 

The  question  concerning  the  age  of  the  "  Lignite  Group  "  is  still  under 
discussion.  Its  settlement  now  rests  almost  wholly  upon  data  furnished 
by  the  life  of  the  Period.  For  the  argument,  consult  (i)  various  papers  in 
R.  73  (every  year  from  1868  to  present),  especially  vol.  for  1874  (pp.  141- 
146,  15 1— 1 55 ),  where  Dr.  A.  C.  Peale  gives  important  summaries  and  ref- 
erences to  authorities ;  (2)  papers  by  Hayden,  Lesquereux  and  others  in 
R.  132  (since  1873);  (3)  articles  by  various  authorities  in  R.  13  [those 
previous  to  1874  recorded  by  Dr.  Peale  {loc.  cit. )];  (4)  the  views  of  the 
author,  based  on  some  study  of  the  lignite  beds  in  N.  W.  Wyoming  are 
given  in  R.  55,  pp.  120,  121,  132,  133  (see  also,  Stratigraphic  Chart 
opposite  p.  103) — at  that  date  the  relation  of  the  Fort  Union  group  to  the 
Green  Riv.  coal  series  was  not  so  clearly  indicated  as  now. 

C.  Foreign,  a.  Similar  history  to  American.  D.  Gen- 
eral Remarks,  a.  Peculiar  association  of  Tertiary  flora  with 
Cretaceous  fauna,  b.  Proof  of  gradual  elevation  of  Rocky 
Mts. ;  change  from  marine  to  fresh-water  beds  not  abrupt,  c. 
Cretaceous  advocates  :  E.  D.  Cope,  O.  C.  Marsh,  J.  S.  New- 
berry (originally  Miocene  in  part),  Clarence  King,  Bannister, 
F.  V.  Hayden  (in  part),  Joseph  Leconte  (in  part),  J.  J.  Steven- 
son, Engelmann,  F.  B.  Meek  (in  part),  Theo.  B.  Comstock 
(Green  River  coal  series  and  coal  and  lignite  beds  of  Wind 
River  Valley,  Shoshone  Plateau  and  canon  of  Buffalo  Fork  of 
Snake  River),  d.  Tertiary  advocates :  F.  V.  Hayden,  F.  B. 
Meek  (in  part),  Jos.  Leidy,  G.  M.  Dawson,  Leo  Lesquereux, 
Joseph  Leconte  (originally  in  Colorado).  e.  Text-books; 
Dana  follows  Hayden  (Eocene),  Le  Conte  adopts  Cretaceous. 

Ref. :— 1  (pp.  403-488,  490,  493,  501,  508),  2 
(chaps,  xxxv,  xxxvii),  3  (pp.  404-475),  10,  13 
(1868,  1874),  47,  55,  65  (Hector,  vol.  xvii), 
73,  116,  117,  123,  131,  132-134. 

DIVISION  E.— CiErVOZOIC  ERA.    . 
A.— TERTIARY  (MAMMALIAN)  AGE.. 

i.  Eocene  Period  (Alabama,  nearly).  A.  N.  Amer- 
ica. I.  C/aibome  Epoch;  II.  Jackson  Epoch;  III.  Vicks- 
burg  Epoch ;  also  I.  Wahsatch  Epoch  {Coryphodon,  Marsh); 
II.  Gree?i  River  Epoch  (Dinoceras) ;  III.  Uintah  Epoch 
(Diplacodon).  a.  S.  C,  Va.,  in  patches;  Miss.,  Ala.,  Georgia; 
Rocky  Mts.,  Uintah,  San  Juan  and  Green  River  basins,     b. 


,  /   ^'  ' '  tv-cf 


HISTORICAL  GEOLOGY.  69 

10,000  ft.  and  more;  coast  areas  marine;  Rocky  Mts.  fresh- 
water, lacustrine ;  varying  greatly,  sands,  clays,  marls,  lime- 
stones, more  or  less  imperfectly  consolidated.  B.  Life.  a. 
5   to   10  per  cent,  of  shells  now  living,  Mammals  all  extinct. 

b.  Palm,  Willow,  Oak,  Grass,  Sedge,  etc.;  genera  modern, 
species  mostly  extinct,  c.  Rhizopods  {Nummulites,  Orbitoides, 
etc.),  modern  genera  of  Molluscs,  Crustaceans  and  Insects; 
Elasmobr.  (Holocephali,  Squalodonts  and  a  few  Batides,  or 
Rays)  and  Ganoids  (with  many  Lepidoganoidei,/  Teliosts) ; 
Amphibians  few,  modern ;  Crocodilia  (mainly  Crocodilus,  but 
some  with  affinities  to  Alligators),  Ophidia  (allied  to  Boa- 
Cott \strictor),  Lacertilia  [G/yptosaitrus,  etc.);  Birds  numerous 
(Odontopteryx),  Waders  (A/etomis),  Cursores  [Diattyma,  Cope), 
etc.,  extinct,  but  several  modern  types,  as  Eagle,  Owl,  Crane, 
etc.  Marsupials  (few,  small),  first  Cetaceans  (Zeuglodon  cetoides 
abundant  in  Ala.,  S.  C,  Ga.),  Manatee  (in  Europe,  not  yet  in 
Amer.),  Perissodactyla — Coryphodon  (5  toes,  low-type  brain), 
Dinoceras  and  Uintatherium  (both  large,  5  toes,  4  to  6  horns, 
extinct  at  close  of  Eocene),  Eohippus,  or  first  Horse  (5  [one  ru- 
dimentary] front  toes,  3  behind,  size  of  fox),  Orohippus  (4  front 
toes)  first  Tapir  (many  small  sp.),  Hyrachyus,  Lophiodon 
(Europe),  first  Rhinoceros  (Amynodon),  Palceosyops,  Diplaco- 
don,  first  Pigs  (Eohyus,  New  Mex.,  etc.,  most  with  4  toes), 
Artiodactyla — -first  Deer  [Oromeryx,  Up.  Eocene),  Tillo- 
dontia — forms  combining  features  of  Bear,  Rodents  and  Car- 
nivores, Rodentia — Squirrels,  small  Insectivora,  large  Car- 
nivora,  many  small  Bats,  low  forms  of  Primates  (Lemurs, 
Marmosets,  with  even  Carnivorous  and  Ungulate  affinities). 
C.  Foreign,  a.  "London  Basin,"  "Paris  Basin,"  etc.  b. 
Life  similar  to  America  (in  Europe),  but  with  special  forms; 
Australian  flora  to-day  similar  to  European  Eocene  flora,  c. 
Mammals  largely  Tapiroid  (Palceotherium,  Anoplotheriutn,  Xi- 
phodon,  etc.)  D.  General  Remarks,  a.  Fresh-water  lakes 
of  Rocky  Mts.  Approach  of  modern  conditions,  b.  Conti- 
nental growth  by  elevation  and  deposition  ;  elevation  in  Plateau 
area,  depression  of  surrounding  plains,  deposition  along  coasts. 

c.  Elevation  of  Pyrenees,  Carpathians,  Appenines,  Julian  Alps, 
etc.  {Middle  Eocene);  W.  Alps  (Mt.  Blanc,  etc.),  close  of 
Eocene,     d.  Climate  sub-tropical  over  wide  area. 

2.  Miocene  Period  (Yorktown).  A.  N.  America. 
I.  White  River  Epoch  {Brotitotherium  Marsh);  II.  Wind 
River  Epoch  (Oreodon);  III.  Oregon  Epoch  (Miohippus). 
a.  Martha's  Vineyard,  N.  J.,  Md.,  Va.  and  southward  along 


7o  GENERAL  GEOLOGY. 

coast;  Rocky  Mts.,  Nebr.,  Colo.,  Wyo.,  Mont.;  Calif.,  Ore- 
gon, b.  5000  ft.,  or  more,  clays,  sands,  etc.,  often  but  little 
indurated;  marine,  east  and  west  coasts;  fresh-water  lacus- 
trine, Rocky  Mts.  B.  Life.  a.  Diatoms  in  "infusorial 
earths"  of  Richmond  (Va.),  Calif,  and  Europe;  Australian 
and  American  flora  less  differentiated  from  Eocene  than  Eu- 
ropean, b.  30  percent,  of  shells  now  living  (Europe);  spe- 
cial forms  of  Invertebrates;  Insects  very  abundant  in  Eu- 
rope, c.  Vertebrates  :  Fishes  in  marine  beds,  but  peculiarly 
absent  from  fresh-water  series  of  interior;  Amphibian  {Andrias 
sciieucheri),  Chelonia — Land  Tortoises  and  Trio7iyx  (in  In- 
terior), Colossochelys  (Europe),  some  Crocodilia,  Ophidia  and 
Lacertilia  of  modern  types ;  Birds  of  modern  types ;  first 
Edentates  in  Amer.,  Cetaceans  {Dolphin  Earn.,  Sperm  Whale, 
etc.),  few  Sirenians,  Ungulata — Mesohippus  (size  of  sheep, 
3  toes  and  rudiment,  in  front,  3  behind),  Miohippus  (near  An- 
chitherium  of  Europe),  extension  of  Rhinoceros  type,  Bron- 
totheridce,  (Titatwtherium,  Megacerops,  etc.)  introduced  and  ex- 
panded to  become  extinct  before  next  Period,  Pigs  (near  Pec- 
cary, abundant  in  Amer.),  Llippopoiamus  (not  yet  in  Amer.), 
Hyopotamus,  Ofeodon,  Camel  tribe  separated  (Procamelus), 
Deer  continued  (by  Leptomeryx,  Cosonyx,  etc.) ;  in  Sewalik 
Hills,  India,  first  Proboscideans,  Dinotheriutn  (combining  char- 
acters of  Elephant,  Tapir,  Hippopotamus  and  Dugong)  Siva- 
therium,  first  Mastodon  (3  sp.),  Elephant  (7  sp.),  Ox,  Sheep, 
etc.;  Rodents  (Hare,  Squirrel,  etc.),  Edentates,  Carnivores 
(Machairodus,  Wolf,  Tiger,  Hyaena),  first  true  Monkeys  in 
Europe  (in  Amer.  synthetic  form  Laopitheais).  C.  Foreign. 
a.  Not  specially  distinct  from  Eocene,  b.  Beds  in  Greenland 
with  plants.  D.  General  Remarks,  a.  Lakes  in  interior 
perhaps  saline,  as  shown  by  absence  of  Fishes,  and  abundance 
of  land  Mammals,  b.  Elevation  of  Coast  Range  and  ejection 
of  some  lavas  through  fissures,  covering  vast  area  in  N.  W.  c. 
Elevations  general  in  other  parts  of  U.  S.  and  abroad,  d. 
Climate  warw-temperate  in  U.  S.  e.  Difference  in  climate 
bet.  N.  and  S. 

3.  Pliocene  Period  (Sumter).  A.  N.America,  a.  N.C., 
S.  C. ;  Niobrara  River,  Loup  Fork,  Platte  Riv. ;  Rocky  Mts., 
South  Pass  (?),  Wind  River  Valley  (?),  Stinking  Water  Riv.  [all 
in  Wyo.] ;  Oregon,  b.  Loams,  sands,  clays,  etc.,  500  ft.  to 
800  ft.,  or  more.  B.  Life.  a.  Plants  not  advanced  materi- 
ally, b.  Invertebrates  of  modern  genera;  majority  of  shells 
are   now  living,      c.  Fishes  largely  Cyprinoid  (Teliosts   like 


HISTORICAL  GEOLOGY.  71 

Carp) ;  one  Crocodile  and  fragments  of  Ophidians ;  Birds  of 
Miocene  genera,  with  new  sp. ;  Edentates  of  great  size  {Mor- 
opus,  Mordtherium)  in  N.  A. ;  Horse  Tribe  represented  by  large 
and  more  modern  forms,  as  Protohippus  (N.  A.),  Hipparion 
(Eur.)  [with  3  toes,  but  only  one  serviceable],  Pliohippus  (N.  A.) 
and  Equus  ;  Rhinoceros  continues  in  Amer.  (becoming  extinct 
here)  and  in  Eur.,  Tapir  extinct  in  N.  A.,  Pig  not  much  ad- 
vanced in  N.  A.,  Oreodon  followed  by  Merychyus  and  allies 
(here  dying  out  in  N.  A.),  Deer  increasing,  Bison  introduced 
in  Amer. ;  first  Mastodons  and  Elephant  in  N.  A. ;  Rodents 
of  modern  genera  Castor,  Hystrix,  Lepus,  etc.  in  N.  A.,  Cavia 
and  others  in  S.  A.  and  some  in  Europe;  Moles;  Cams, 
Machairodus  (S.  A.),  first  Amer.  Bears  (Leptarctus.)  C.  For- 
eign, a.  Half  of  Sicily;  marine  and  inland  deposits  in  Gt. 
Brit,  and  elsewhere.  D.  General  Remarks,  a.  Continua- 
tion of  elevation,     b.  Reduction  of  temperature,  etc. 

4.  Review  of  Tertiary  Age.  a.  Relations  of  continents 
and  contained  life  during  successive  Periods. 

B.—Q  UA  TERNAR  Y  A  GE. 

1.  Glacial  Period.  A.  N.  America,  a.  N.  E.,  from 
present  glacial  line  S.  to  Lat.  390,  W.  to  Long.  980;  local  in 
Rocky  Mts.,  N.  and  S.  to  Lat  350;  Tenn.,  W.  Va.,  etc.  b.  Ex- 
tending to  height  of  6000  ft.  above  Atlantic  in  places  (Mt. 
Washington,  etc.) ;  scratchings,  groovings,  moraines.  B.  Life. 
[Given  below  under  4].  C.  Foreign,  a.  Deposits  and  phe- 
nomena similar  to  American.  D.  General  Remarks,  a. 
Effects  and  deposits  quite  similar  to  those  of  present  glacier 
regions  [see  ante, -p.  42].  b.  Great  Lakes,  "parallel  valleys" 
of  Cent.  N.  Y.  lakes,  Hudson  River,  etc.,  more  or  less  modi- 
fied, c.  Remarks  on  local  action  in  Rocky  Mts.  d.  Eleva- 
tion northward  (southward  in  S.  Hem.)  e.  Course  of  drift 
material  S.  E.  or  S.  W.  (in  general),  as  shown  by  groovings  and 
character  of  boulders,  f.  Agassiz's  theory  of  Amazonian  drift 
refuted,  g.  Forced  emigrations  of  plants  and  animals  [Dr. 
Gray,R.  13  (1857,  xxiii,  p.  62) ;  A.  R.  Grote,  R.  78  (B,  p.  222) ; 
and  others],  h.  Fjords,  i.  Iceberg  action  along  coasts,  j. 
Note : 

These  subjects  are  fully  discussed  in  text-books  and  in  special  works  re- 
ferred to  below  [Ref.,  p.  76]. 

2.  Champlain  Period.  A.  N.  America.  I.  Dihivian 
Epoch  [Erie  clays).  a.  Wide-spread,  but  following  largely 
courses  of  old  glaciers,  with  greater  southward  extension,     b. 


72  GENERAL  GEOLOGY. 

Boulder  clay,  drift,  largely  stratified  but  also  nntnodified,  with 
plant  accumulations;  clays  abundant,  with  sands  and  gravels 
[Orange  sand,  Lower  Miss.;  Saxicava  sands,  L.  Champlain) 
often  irregularly  disposed  as  in  modern  fluvial  and  lacustrine 
deposits.  II.  Alhivian  Epoch  (Loess),  a.  Distribution  same 
as  Diluvian.  b.  Deposits  (loess,  etc.)  in  more  quiet  waters, 
along  river,  lake  and  sea  borders.  B.  Life.  [Given  below 
under  4].  C.  Foreign,  a.  Very  similar  to  American.  D. 
General  Remarks,  a.  Melting  of  ice-sheet,  due  to  depres- 
sion, b.  Flooding  of  land,  obscuring  and  silting  up  river  val- 
leys, c.  Formation  of  caverns,  d.  Greater  height  of  deposits 
northward  above  neighboring  water-levels.  e.  Subsidence 
greatest  in  interior,     f.  Seas,  lakes  and  rivers. 

(1)  Champlain  Sea  extended  over  S.  Me.,  up  St.  Lawrence  nearly  to 
L.  Ontario,  including  also  L.  Champlain  area,  as  shown  by  marine  fossils. 

(2)  Inland  Lakes ;  (a)  over  region  of  Gt.  Lakes,  possibly  continuous 
with  (/>)  immense  body  of  water  in  Brit.  Amer.,  outlined  by  G.  M.  Daw- 
son [R.  65  (vol.  xxxi,  p.  620),  134  (chaps,  ix,  x)]  ;  both  connecting  with 
Mississippi  and  Missouri  drainage  system. 

(3)  Hudson,  Ohio,  Mississippi  and  nearly  all  northern  rivers  (as  about 
Ithaca)  much  wider  than  now  (Mississippi  from  50-75  miles). 

3.  Recent  Period.  A.  N.America.  I.  Reitideer  (Sec- 
ond Glacial)  Epoch.  II.  Modern  Epoch,  a.  Distribution 
Continental,  b.  Terraces  bordering  sea,  lakes  and  rivers,  bone 
breccias,  etc.,  and  deposits  of  modern  character,  travertine, 
stalactites,  etc.  B.  Life.  [Included  under  4,  below].  C. 
Foreign.  More  extensive  and  effective  in  some  particulars. 
D.  General  Remarks,  a.  Re-elevation  of  land  still  con- 
tinuing, b.  Increase  of  land  along  coasts,  c.  Separation  of 
Gt.  Lakes  and  others  by  draining  of  Inland  Lakes,  d.  Second 
glacial  epoch  less  evident  in  Amer.  than  in  Eur.,  but  probably 
existent  here.  e.  Amazonian  diminution  and  terrace  forma- 
tions. 

4-  Life  of  Quaternary  Age.  a.  Preserved  in  marshes, 
peat-bogs,  forest-beds,  bone-caverns,  and  in  ice.  b.  Plants 
and  Molluscs  mainly  of  living  species,  mammals  chiefly  extinct. 
c.  Northward  migrations  of  Plants  and  Molluscs  since  earlier 
periods  of  Quaternary,  d.  Mammals  extremely  large;  not 
always  easily  referred  to  Epoch  or  Period : 

(1)  AT.  America  (promising  field  for  investigation,  in  caves,  etc.)  Large 
Hordes,  Ox,  Bison  lalifrons,  2  sp.  near  Musk-Ox,  gigantic  Stag,  Tapir, 
Beaver  (Casloroides),  Elephas  primigenius  (northward),  E.  Americanus, 
Mastodon  Americanus,  Whale  {Beluga  Vermontana),  Megatherium,  My- 
lodon,  Megalonyx,  Bear,  Lion,  Raccoon,  and  others,  with  Birds  (Turkey, 
Crane,  etc.) 

(2)  S.  America.     Very  many  and  immense  Edentates  like  N.  Amer. 


PRE-HISTORIC  AR CH^E QLOGY.  73 

and  others  (as  Glyptodon,  Chlamydotherium,  Pachy theriuni)  \  also  special 
Mastodon  and  other  peculiar  forms. 

(3)  Europe  and  Asia.  Immense  Carnivora — Tiger,  Wolf,  Machairo- 
dns,  Cave  Bear  (Eur.  Cont. ),  Cave  Hyaena  (Gt.  Brit.), allied  to  present 
African  forms  ;  Mammoth,  and  other  Elephants,  woolly-haired  Rhinoceros 
(A',  tichorhinus),  Grizzly  Bear,  Beaver  (  Trogontherium),  etc.  ;  fauna  with 
fades  of  present. 

(4)  Australia.     Immense  Marsupials  {Diprotodon,  etc.) 

e.  In  supposed  earliest  glacial  deposits  ("Cromer  Forest 
Bed"),  Cave  Bear,  Megaceros,  Trogontherium,  Elephas  (3  sp.). 
Hippopotamus  major,  2  sp.  of  Rhinoceros,  Machairodus  latidens. 
[Several  of  preceding  are  Pliocene  types,  and  last  named  is 
even  Miocene]. 

Ref.1 :— 1  (pp.  527-573),  2  (chap,  xli),  3  (pp. 
5 x  3-5 57).  9>  IO>  r3i  (many  papers,  for  which 
consult  General  Index),  22,  37,  46,  47,  55, 
65  {Index),  67  (occasional  papers),  73  [In- 
dices), 78,  84,  87,  88,  104,  106,  112,  128  (es- 
pecially vol.  II,  pp.  1-83),  130,  134,  135,  136, 
137- 


PART  VII.-PRE-HISTORIC  ARCHEOLOGY. 

1.  Scope,  etc.  a.  Relations  to  Geology,  b.  Relations 
to  written  History,  c.  Material  for  study,  d.  Nature  of  the 
records. 

DIVISION  A.— ANTIQUITY  OF  MAN. 

1.  Estimates,  a.  Chronology  of  Usher  and  Petavius 
(less  than  6000  yrs.)  quite  generally  regarded  as  far  too  short. 
b.  Baron  Bunsen,  from  philological  data,  20,000  yrs.  c.  Sir 
Chas.  Lyell,  estimating  growth  of  Somme  Delta  on  basis  of 
Mississippi  deposition,  considers  age  of  remains  in  former 
100,000  yrs.  d.  Sir  John  Lubbock,  basing  calculations  on  ex- 
cavation of  valley  of  Somme,  100,000  yrs.  to  240,000  yrs.  e. 
Estimates  based  on  cosmical  changes  make  period  fully  as 
great,     f.  Other  calculations. 

2.  Geological  Age  of  Earliest  Human  Relics,     a. 

1  Local  and  fragmentary  papers  upon  the  deposits  and  phenomena  of  this  AGE  are 
very  numerous,  but  much  scattered.  Students  who  begin  to  study  the  subject  will  soon 
find  references  from  paper  to  paper,  however,  and  similar  references  are  made  in  most 
'  general  works  upon  the  Drift  Period. 


74  GENERAL  GEOLOGY. 

Undoubted  remains  in  Quaternary;  some  think  in  Pliocene,  a 
few  even  Miocene,  b.  Difficulty  of  determining  horizon  of 
deposits,     c.   Reports  often  founded  on  unreliable  evidence. 

3.  Age  of  Man  in  North  America,  a.  A.  C.  Koch 
reports  Mastodon  from  Missouri,  stoned  to  death  and  burned. 
b.  Plain  underlying  New  Orleans,  alluvium  500  ft.  thick,  with 
several  cypress  forests;  human  remains  found  at  depth  of  16 
ft.,  at  foot  of  tree  of  4th  forest  below  surface  [see  R.  46]. 

Ref. :— 1,  2,  3,  7,  24,  46  (vol.  i),  70,  89,  138 

(chap,  xii),  140. 

DIVISION  B.-CHRONOLOCJY. 

1.  Subdivisions,  a.  Based  in  part  upon  Lartet's  system. 
b.  The  grouping  below  shows  geological  relations  of  divisions 
adopted. 

I.  Psychozoic  [Caenozoic]  Era. 

Age  A. — Pre-Historic.  Period  i.  Stone.  EpocJi  L.  Pa- 
leolithic, or  Mammoth  (Dupont),  equivalent  of  Champlain  ; 
rude  stone  implements ;  extinct  Elephant,  Rhinoceros,  Horse, 
Hippopotamus,  Cave-animals.  Epoch  II.  Reindeer.  Medium 
stone  implements,  split  marrow-bones  and  charcoal;  extinct  El- 
ephant, Urus,  Cave-Bear,  Cave-Lion,  Cave-Hyaena,  etc. ;  Horse, 
Reindeer  and  other  living  northern  species  (Aurochs,  Ibex,  Elk, 
etc.)  Epoch  III.  Neolithic,  equivalent  to  large  part  of  Modern 
Period.  Polished 'stone  implements,  pottery,  kjokkenmodding, 
Pfahlbauten ;  bones  of  dog  and  other  living  quadrupeds. 
Period  2.  Bronze,  part  of  Modern  Period.  Bronze  imple- 
ments, earth-works,  etc. ;  living  Mammals.  Period  3.  Iron, 
close  of  Modern  and  beginning  of  Historical  Period.  Iron 
implements,  hieroglyphs,  mounds,  etc. 

Age  B. — Historic,  within  historical  times.  Written  rec- 
ords, traditions,  etc. 

N.  B. — Stone  Period  continued  to  Historical  Period  in  Amer., 
and  a  somewhat  restricted  Copper  Period  is  exemplified  which  must 
have  been  synchronous  with  a  portion  of  one  of  the  Periods  above,  in 
Europe. 

DIVISION  C— PRE-HISTORIC  AGE. 

I.  Stone  Period.  I.  Palceolithic  Epoch,  a.  River-border 
deposits,  entombing  bones  of  man  associated  with  those  of 
extinct  Mammals  and  living  shells. 

Mammoth  and  other  Elephant,  2  sp.  of  Rhinoceros,  1  Bear,  1  Hysena, 
I  Tiger,  2  sp.  of  Ox  {Bos),  Musk  Ox,  2  sp.  (?)  of  Horse,  3  sp.  of  Deer, 
1  Hippopotamus,  I  Hog,  1  Lemming;  52  Molluscs,  of  which  42  now  live 
in  Sweden. 


PRE-HISTORIC  AR CH.E OLOGY.  75 

b.  Cavern  deposits  (older),  Bear  caves  on  Eur.  Cont.,  Hy- 
czna  caves  in  Brit.  Is.  ;  some  British  and  Belgian  caverns  prob- 
ably o(  this  Epoch,  c.  Environment,  including  :  (^Topogra- 
phy, (2)  Climate,  (3)  Enemies,  (4)  Food,  (5)  Clothing,  (6) 
Mental  condition,  (7)  Morals,  etc.  d.  Degree  of  civilization, 
as  shown  by  (1)  Tools,  (2)  Weapons,  (3)  other  manufactures 
(as  pottery,  etc.)  II.  Reindeer  Epoch,  a.  Cavern  deposits 
(newer) :  stone  implements  better  fashioned  than  Palaeolithic 
Epoch,  bone  implements,  bone-carvings,  b.  Reindeer  abun- 
dant, with  extinct  Cave  Mammals,  similar  to  Palaeolithic,  c. 
Cavern  deposits  of  S.  France,  Sicily,  etc.,  probably  of  this  Epoch 
d.  Tall  men,  round-headed  like  Laplander,  tibiae  often  flatten- 
ed (platycnemic)  [See  H.  Gillman,  R.  13  (Jan'y,  1874),  78 
(vol.  xxiv,  1875,  B,  p.  316),  147  (6th  Rep't)]  and  skulls  some- 
times perforated.  III.  Neolithic  Epoch,  a.  Shell-heaps,  or 
kjokkenmodding  ("kitchen-middens").  b.  Lake-Dwellings, 
or  Pfahlbauten  (Crannoges).  c.  Tumuli,  etc.  d.  Difficulties 
of  determining  synchronism;  views  of  different  authorities,  e. 
Pfahlbauten  remains:  72  sp.  (10  Fishes,  4  Reptiles,  26  Birds, 
32  Mammals),  6  domesticated,  viz. :  Dog,  Pig,  Horse,  Goat, 
Sheep,  Ox  (2  var.)     f.   Special  consideration  of  certain  relics: 

(1)  Polished  Stone  Imple?nents.  (a)  Certainly  100,000  or  more  speci- 
mens in  collections.  (<$)  Comprise  flint-flakes,  spear-heads,  arrow-heads, 
axes,  scrapers,  awls,  etc.;  spindle-whorls,  sinkers,  etc.  (c)  Material 
obsidian,  quartzyte,  green-stone  (dioryte,  etc.),  porphyrine,  etc.  (d)  Mode 
of  manufacture  [Torquemada,  Hernandez,  Baines,  etc. ;  quoted  in  R.  138, 
pp.  88-90,  with  illus.] 

(2)  Bone  Implements  comprise  harpoons,  knives,  awls,  chisels  (?), 
handles  for  tools  and  weapons,  perforated  teeth  (used  as  charms). 

(3)  Tumuli  and  Monuments,  (a)  Dolmens,  menhirs,  cromlechs,  stone- 
circles,  etc.  (b)  Chambered  tumuli,  (c)  Used  as  dwellings  or  tombs  or 
both,  (d)  Many  Druidical  and  other  modern  forms,  but  large  number 
undoubtedly  Pre-historic,  probably  of  Stone  Period,  and,  perhaps, 
mainly  A'eolithic. 

(4)  Pottery,  (a)  Urns,  incense-cups,  food-vases,  drinking-cups,  etc. 
(b)  In  ornamentation,  etc.,  indicate  progressive  art. 

(5)  Other  Relics,  (a)  Rude  rock  sculptures,  (b)  Coarse  cloth  (woven). 
(<:)  Articles  of  food,  as  grain,  fruits,  etc.     (d)  Remains  of  fire,  etc. 

2.  Bronze  Period,  a.  Bronze  implements,  with  few 
stone,  all  of  higher  type  than  before,  b.  Men  more  highly 
civilized,  c.  Less  to  contend  with  from  lower  animals  and 
greater  skill  in  the  chase,  d.  More  warlike,  more  and  better 
weapons. 

3.  Iron  Period,  a.  Overlaps  period  of  written  history. 
b.  Beyond  the  scope  of  Geology,  except  in  special  cases. 

4.  Ancient  Modes  of  Burial,  a.  Observations  of  Sir 
R.  C.  Hoare  and  Mr.  Bateman  combined  as  below : 


76 


GENERAL  GEOLOGY. 


Implements. 

CORPSE. 

Total. 

Contracted. 

Burnt. 

Extended. 

Position 
Uncertain. 

None, 
Stone, 
Bronze, 
Iron, 
Total, 

36 

55 
19 

2 

223 
53 
59 

3 

6 
3 

7 
21 

19 

32 
15 
11 

284 

143 
IOO 

37 

112 

338 

37 

77 

564 

Ref.  : — 1,  2,  3,  24,  46.  51,  77  (Index),  78  (vari- 
ous papers),  88  (ditto),  89,  138,  139,  140,  143, 
147. 


DIVISION  ».- 


-NORTH  AMERICAN  ARCHE- 
OLOGY. 


1.  Earthworks.  I.  Defensive  Inclosures;  II.  Sacrificial 
Mounds;  III.  Sepulchral  Mounds ;  IV.  Temple  Mounds ;  V. 
Animal  Mounds;  VI.  Miscellaneous  Mounds :  VII.  C/z^1" 
Dwellings. 

2.  Stone  and  Bronze  Periods  not  Synchronous 
with  European,  a.  Even  N.  Amer.  Indians  relics  of  Stone 
Period,  having  no  knowledge  of  use  of  iron  at  date  of  first 
settlements.  b.  Possible  Palaeolithic  implements  in  various 
parts  of  U.  S.  c.  Numerous  Neolithic  implements,  many  of 
recent  date,  and  some  forms  still  in  use  by  Shoshones  and  other 
tribes,  d.  Bronze  Period  may  be  wholly  or  in  part  represented 
by 

3.  Copper  Period,  a.  Copper  implements,  especially  in 
L.  Superior  region  (Isle  Royal,  Keewenaw  Penin.,  etc.)  b. 
Copper  mined  and  hammered  into  useful  forms,  by  stone  im- 
plements, from  lumps  of  native  metal. 

4.  Pottery,  a.  Often  highly  ornamented,  b.  American 
forms  frequently  related  to  Peruvian,  etc.  c.  Pipes,  many  in 
shape  of  animals,  and  even  S.  A.  Manatee  represented. 

5.  Ornaments,  a.  Shells  (often  marine  farmland),  beads, 
bracelets,  necklaces,  etc.     b.  Carvings,  etc. 

6.  Pre-Historic  Agriculture,  a.  "  Garden  beds,"  very 
ancient  in  many  cases,     b.  Now  covered  by  second  forest. 

Ref.  :— 1,  2,  3,  46,  50,  51,  55,  70;  various  pa- 
pers in  73,  77,  78  and  88;  89,  91,  104,  132, 
138,  144,  145-148. 


CONCLUSION.  77 

PART  VIII -PHILOSOPHICAL  GEOLOGY. 

Devoted  to  the  amplification,  in  Review,  of  a  few  such  im- 
portant topics  as  are  given  below  : 
i.  Length  of  Geologic  Time. 

2.  Growth  of  Continents. 

3.  Evolution  of  Life  upon  the  Globe. 

4.  Catastrophism  versus  Secular  Movement. 

5.  Cosmical  Influences,  including 

6.  Cause  of  Cold  of  Glacial  Periods. 

7.  Legitimate  Use  of  Imagination  in  Geology. 


PART  IX.-CONCLUSION. 

1.  Importance  of  Care  in  Observation. 

2.  Temporary  Value  of  Theories. 

3.  Parting  Hints  : 

"  Hold  fast  to  that  which  is  good." 

"  If  truth  do  anywhere  manifest  itself,  seek  not  to  smother  it 
with  glossing  and  vain  delusions,  but  acknowledge  the  greatness 
thereof  and  consider  it  thy  greatest  victory  when  the  same  doth 
prevail  over  thee." 

"  The  greatest  friend  of  Truth  is  Time  ;  her  greatest  enemy  is 
Prejudice,  and  her  constant  companion  is  Humility." 


LIST  OF  REFERENCES. 

Note. — In  the  body  of  the  Outline  the  titles  given  in  this  list  are  re- 
ferred to  by  their  numbers. 

1.  Dana,  J.  D.     Manual  of  Geology  [Ed.,  1874]. 

2.  Jukes  and  Geikie.     Manual  of  Geology  [3d  Ed.] 

3.  Le  Conte,  Joseph.     Elements  of  Geology,  1878. 

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8.  Geikie,  Arch.     Elementary  Lessons  in  Physical  Geography. 

9.  Page,  David.     Advanced  Text  Book  of  Geology. 

10.  Dana,  J.  D.      Text  Book  of  Geology.     [Abridgement  of  I]. 

11.  Young.     Physical  Geography.     [Putnam's  Advanced  Series].      Use 

with  great  caution  ;  contains  a  few  serious  errors. 

12.  Owen,  R.     Key  to  Geology  of  Globe. 

13.  Periodical  (Monthly).     American  Journal  Science  and  Arts. 

14.  Wallace,  A.  R.     Malay  Archipelago. 

15.  Periodical  (Annual).     Journal  Indian  Archipelago,  etc. 

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18.  Flammarion.      The  Atmosphere. 

19.  Blodgett,  Lorin.     Climatology  of  United  States. 

20.  Meyer,  Albert  J.     Reports,  Chief  Signal  Officer,  U.  S.  Army. 

21.  Winchell,  Alex.     Michigan;   Climate,  Topography,  etc. 

22.  Hitchcock,  C.  H.  and  Assistants.     Geology  of  N.  H.  [3  Vols.] 

23.  Huxley,  T.  H.     Physiography. 

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27.  Reclus,  Elisee.      The  Earth. 

28.  Thomson,  Wyville.     The  Challenger  Expedition. 

29.  Dana,  J.  D.     System  of  Mineralogy. 

30.  Dana,  J.  D.     Manual  of  Mineralogy  [Last  Edition], 

31.  Dana,  E.  S.  and  J.  D.     Text  Book  of  Mineralogy. 

32.  Comstock,  Theo.  B.     Classification  of  Rocks. 

33.  Comstock,  Theo.  B.     Descriptive  Classification  of  Rocks.      Used  in 

Lithological  work,  Cornell  Univ.  Geol.  Lai.     Pafyrografhic  sheets. 

79 


80  REFERENCES. 

34.  Collins,  J.  H.     First  Book  of  Mineralogy.     [Putnam's  Element  Ser.  ] 

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100.  Agassiz.  L.     Atlas  of  Plates  accompanying  preceding. 

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130.  Whitney,  J.  D.     Geological  Survey  of  California. 

131.  King,  Clarence.     U.  S.  Geological  Survey  of  40th  Parallel. 

132.  Bulletins.     U.  S.  Geol.  Survey  of  Territories  (Hayden). 

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134.  Dawson,  Geo.  M.     Report  on  Geology,  etc.,  along  49th  Parallel. 

135.  Foote,  Chas.  W.      Notes  on  Physical  Geology  of  Cayuga   Lake, 

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For  other  references  consult  Royal  Society  [London]  Catalogue  of  Sci- 
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list,  and  many  others,  have  published  numerous  papers  bearing  upon  the 
subjects  here  treated. 

N.  B. — Of  the  references  included  in  the  above  List,  the  following  are 
accessible  to  students  in  the  Library  of  the 


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